Retirement Benefits - Schedule of Fair Value Disclosures (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	$ 13,658.4	$ 13,708.7	$ 13,195.8
Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	2,565.8	2,580.3	$ 2,492.5
U.S. | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,905.6	1,379.7
U.S. | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	184.2	127.0
International | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,517.3	1,408.9
International | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	103.7	89.9
Developed markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	2,343.2	2,783.9
Developed markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	63.0	74.9
Developed markets - repurchase agreements | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	(641.0)	(772.8)
Emerging markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	320.4	295.6
Emerging markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	26.0	23.4
Hedge funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	3,057.6	3,125.9
Hedge funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	285.2	281.2
Equity-like funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	3,931.5	4,093.7
Equity-like funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	346.1	335.1
Cash value of trust owned insurance contract | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,464.9	1,526.5
Real estate | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	450.9	369.7
Real estate | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	28.4	24.5
Other | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	772.9	1,024.1
Other | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	64.3	97.8
Quoted Prices in Active Markets for Identical Assets (Level 1) | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,408.9	1,409.2
Quoted Prices in Active Markets for Identical Assets (Level 1) | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	129.9	130.1
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	602.4	490.5
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	56.9	44.2
Quoted Prices in Active Markets for Identical Assets (Level 1) | International | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	453.7	441.2
Quoted Prices in Active Markets for Identical Assets (Level 1) | International | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	41.0	38.2
Quoted Prices in Active Markets for Identical Assets (Level 1) | Developed markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	20.6	21.2
Quoted Prices in Active Markets for Identical Assets (Level 1) | Developed markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Developed markets - repurchase agreements | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	13.2
Quoted Prices in Active Markets for Identical Assets (Level 1) | Emerging markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	21.0	10.4
Quoted Prices in Active Markets for Identical Assets (Level 1) | Emerging markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Hedge funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Hedge funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity-like funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity-like funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash value of trust owned insurance contract | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Real estate | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	301.0	261.9
Quoted Prices in Active Markets for Identical Assets (Level 1) | Real estate | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	28.4	24.5
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	10.2	170.8
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	3.6	23.2
Significant Other Observable Inputs (Level 2) | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,918.7	2,223.3
Significant Other Observable Inputs (Level 2) | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,520.9	1,603.5
Significant Other Observable Inputs (Level 2) | U.S. | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.3	0.3
Significant Other Observable Inputs (Level 2) | U.S. | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Other Observable Inputs (Level 2) | International | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	336.7	333.4
Significant Other Observable Inputs (Level 2) | International | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Other Observable Inputs (Level 2) | Developed markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	2,161.9	2,597.3
Significant Other Observable Inputs (Level 2) | Developed markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	63.0	74.9
Significant Other Observable Inputs (Level 2) | Developed markets - repurchase agreements | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	(641.0)	(786.0)
Significant Other Observable Inputs (Level 2) | Emerging markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	34.9	35.7
Significant Other Observable Inputs (Level 2) | Emerging markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Other Observable Inputs (Level 2) | Hedge funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Other Observable Inputs (Level 2) | Hedge funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Other Observable Inputs (Level 2) | Equity-like funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Other Observable Inputs (Level 2) | Equity-like funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Other Observable Inputs (Level 2) | Cash value of trust owned insurance contract | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,464.9	1,526.5
Significant Other Observable Inputs (Level 2) | Real estate | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Other Observable Inputs (Level 2) | Real estate | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Other Observable Inputs (Level 2) | Other | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	25.9	42.6
Significant Other Observable Inputs (Level 2) | Other | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	(7.0)	2.1
Significant Unobservable Inputs (Level 3) | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	9.5	25.2
Significant Unobservable Inputs (Level 3) | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.9	2.4
Significant Unobservable Inputs (Level 3) | U.S. | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | U.S. | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | International | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | International | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Developed markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.1	0.1
Significant Unobservable Inputs (Level 3) | Developed markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Developed markets - repurchase agreements | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Emerging markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Emerging markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Hedge funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Hedge funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Equity-like funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	9.4	25.1
Significant Unobservable Inputs (Level 3) | Equity-like funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.9	2.4
Significant Unobservable Inputs (Level 3) | Cash value of trust owned insurance contract | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Real estate | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Real estate | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Other | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) | Other | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Investments Valued at Net Asset Value | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	10,321.3	10,051.0
Investments Valued at Net Asset Value | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	914.1	844.3
Investments Valued at Net Asset Value | U.S. | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,302.9	888.9
Investments Valued at Net Asset Value | U.S. | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	127.3	82.8
Investments Valued at Net Asset Value | International | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	726.9	634.3
Investments Valued at Net Asset Value | International | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	62.7	51.7
Investments Valued at Net Asset Value | Developed markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	160.6	165.3
Investments Valued at Net Asset Value | Developed markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Investments Valued at Net Asset Value | Developed markets - repurchase agreements | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Investments Valued at Net Asset Value | Emerging markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	264.5	249.5
Investments Valued at Net Asset Value | Emerging markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	26.0	23.4
Investments Valued at Net Asset Value | Hedge funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	3,057.6	3,125.9
Investments Valued at Net Asset Value | Hedge funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	285.2	281.2
Investments Valued at Net Asset Value | Equity-like funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	3,922.1	4,068.6
Investments Valued at Net Asset Value | Equity-like funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	345.2	332.7
Investments Valued at Net Asset Value | Cash value of trust owned insurance contract | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Investments Valued at Net Asset Value | Real estate | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	149.9	107.8
Investments Valued at Net Asset Value | Real estate | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	0.0	0.0
Investments Valued at Net Asset Value | Other | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	736.8	810.7
Investments Valued at Net Asset Value | Other | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	$ 67.7	$ 72.5