Employee plans - Schedule of Plan Assets at Fair Value (Details) - USD ($) $ in Millions | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 |
Pension Plans | U.S. Plans | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | $ 2,440.1 | $ 3,139.3 | $ 3,847.8 |
Pension Plans | U.S. Plans | Fair Value | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 1,945.9 | 2,688.7 | |
Pension Plans | U.S. Plans | Fair Value | Common Stocks | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 544.6 | 654.3 | |
Pension Plans | U.S. Plans | Fair Value | Equity Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 383.2 | 398.9 | |
Pension Plans | U.S. Plans | Fair Value | U.S. Govt. Securities | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 291.7 | 413.2 | |
Pension Plans | U.S. Plans | Fair Value | Other Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 293.8 | 479.3 | |
Pension Plans | U.S. Plans | Fair Value | Debt Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 185.5 | 525.2 | |
Pension Plans | U.S. Plans | Fair Value | Real Estate Investment Trusts | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 87.1 | 154.1 | |
Pension Plans | U.S. Plans | Fair Value | Derivatives | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 95 | (53.7) | |
Pension Plans | U.S. Plans | Fair Value | Pooled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 92.1 | 108.4 | |
Pension Plans | U.S. Plans | Fair Value | Cumulative futures contracts variation margin paid to (received from) brokers | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 5.3 | (5.8) | |
Pension Plans | U.S. Plans | Fair Value | Cash | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 0.8 | 0.2 | |
Pension Plans | U.S. Plans | Fair Value | Receivables | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 9.3 | 15.7 | |
Pension Plans | U.S. Plans | Fair Value | Payables | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | (42.5) | (1.1) | |
Pension Plans | U.S. Plans | Level 1 | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 890.2 | 1,234.5 | |
Pension Plans | U.S. Plans | Level 1 | Common Stocks | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 543.2 | 652.4 | |
Pension Plans | U.S. Plans | Level 1 | U.S. Govt. Securities | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 291.7 | 413.2 | |
Pension Plans | U.S. Plans | Level 1 | Real Estate Investment Trusts | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 87.1 | 154.1 | |
Pension Plans | U.S. Plans | Level 1 | Derivatives | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | (4.7) | 5.8 | |
Pension Plans | U.S. Plans | Level 1 | Cumulative futures contracts variation margin paid to (received from) brokers | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 5.3 | (5.8) | |
Pension Plans | U.S. Plans | Level 1 | Cash | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 0.8 | 0.2 | |
Pension Plans | U.S. Plans | Level 1 | Receivables | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 9.3 | 15.7 | |
Pension Plans | U.S. Plans | Level 1 | Payables | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | (42.5) | (1.1) | |
Pension Plans | U.S. Plans | Level 2 | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 1,055.7 | 1,454.2 | |
Pension Plans | U.S. Plans | Level 2 | Common Stocks | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 1.4 | 1.9 | |
Pension Plans | U.S. Plans | Level 2 | Equity Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 383.2 | 398.9 | |
Pension Plans | U.S. Plans | Level 2 | Other Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 293.8 | 479.3 | |
Pension Plans | U.S. Plans | Level 2 | Debt Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 185.5 | 525.2 | |
Pension Plans | U.S. Plans | Level 2 | Derivatives | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 99.7 | (59.5) | |
Pension Plans | U.S. Plans | Level 2 | Pooled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 92.1 | 108.4 | |
Pension Plans | U.S. Plans | Level 3 | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 0 | 0 | |
Pension Plans | U.S. Plans | Level 3 | Common Stocks | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 0 | 0 | |
Pension Plans | U.S. Plans | Plan assets measured using NAV as a practical expedient | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 494.2 | 450.6 | |
Pension Plans | U.S. Plans | Plan assets measured using NAV as a practical expedient | Equity Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | | 0 | |
Pension Plans | U.S. Plans | Plan assets measured using NAV as a practical expedient | Debt Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 65 | 78.6 | |
Pension Plans | U.S. Plans | Plan assets measured using NAV as a practical expedient | Other, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 147.4 | 112.5 | |
Pension Plans | U.S. Plans | Plan assets measured using NAV as a practical expedient | Private Real Estate | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 238.9 | 234.2 | |
Pension Plans | U.S. Plans | Plan assets measured using NAV as a practical expedient | Private Equity | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 42.9 | 25.3 | |
Pension Plans | International Plans | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 1,444.3 | 2,431.6 | 3,129.4 |
Pension Plans | International Plans | Fair Value | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 411.1 | 949.8 | |
Pension Plans | International Plans | Fair Value | Common Stocks | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 0 | 0 | |
Pension Plans | International Plans | Fair Value | Equity Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | | 34.1 | |
Pension Plans | International Plans | Fair Value | Other Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 2.8 | 3 | |
Pension Plans | International Plans | Fair Value | Insurance Contracts | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 100.3 | 110.2 | |
Pension Plans | International Plans | Fair Value | Debt Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 126.5 | 383.8 | |
Pension Plans | International Plans | Fair Value | Real Estate Investment Trusts | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | | | |
Pension Plans | International Plans | Fair Value | Derivatives | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | | | |
Pension Plans | International Plans | Fair Value | Other, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 15 | 390 | |
Pension Plans | International Plans | Fair Value | Pooled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 25.3 | | |
Pension Plans | International Plans | Fair Value | Cash | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 20.5 | 28.7 | |
Pension Plans | International Plans | Fair Value | Receivables | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 120.9 | | |
Pension Plans | International Plans | Fair Value | Payables | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | (0.2) | | |
Pension Plans | International Plans | Level 1 | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 141.2 | 28.7 | |
Pension Plans | International Plans | Level 1 | Common Stocks | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 0 | 0 | |
Pension Plans | International Plans | Level 1 | Cash | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 20.5 | 28.7 | |
Pension Plans | International Plans | Level 1 | Receivables | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 120.9 | | |
Pension Plans | International Plans | Level 1 | Payables | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | (0.2) | | |
Pension Plans | International Plans | Level 2 | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 169.6 | 810.9 | |
Pension Plans | International Plans | Level 2 | Common Stocks | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 0 | 0 | |
Pension Plans | International Plans | Level 2 | Equity Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | | 34.1 | |
Pension Plans | International Plans | Level 2 | Other Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 2.8 | 3 | |
Pension Plans | International Plans | Level 2 | Debt Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 126.5 | 383.8 | |
Pension Plans | International Plans | Level 2 | Real Estate Investment Trusts | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | | | |
Pension Plans | International Plans | Level 2 | Derivatives | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | | | |
Pension Plans | International Plans | Level 2 | Other, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 15 | 390 | |
Pension Plans | International Plans | Level 2 | Pooled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 25.3 | | |
Pension Plans | International Plans | Level 3 | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 100.3 | 110.2 | |
Pension Plans | International Plans | Level 3 | Common Stocks | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 0 | 0 | |
Pension Plans | International Plans | Level 3 | Insurance Contracts | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 100.3 | 110.2 | 127.5 |
Pension Plans | International Plans | Plan assets measured using NAV as a practical expedient | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 1,033.2 | 1,481.8 | |
Pension Plans | International Plans | Plan assets measured using NAV as a practical expedient | Equity Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 0 | 404.5 | |
Pension Plans | International Plans | Plan assets measured using NAV as a practical expedient | Debt Securities, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 788.8 | 1,077.3 | |
Pension Plans | International Plans | Plan assets measured using NAV as a practical expedient | Other, Commingled Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 244.4 | | |
Pension Plans | International Plans | Plan assets measured using NAV as a practical expedient | Private Real Estate | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | | | |
Pension Plans | International Plans | Plan assets measured using NAV as a practical expedient | Private Equity | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | | | |
Other Postretirement Plans | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 5.2 | 5.6 | 6 |
Other Postretirement Plans | U.S. Plans | Insurance Contracts | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | 5.2 | 5.6 | |
Other Postretirement Plans | U.S. Plans | Level 3 | Insurance Contracts | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Total pension plan assets | $ 5.2 | $ 5.6 | $ 6 |