Retirement Benefits (Schedule of Fair Value Disclosures) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	$ 13,195.8	$ 16,416.0	$ 14,579.0
Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	2,492.5	3,361.4	$ 3,227.0
U.S. | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,132.4	1,325.4
U.S. | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	104.2	124.7
International | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,177.1	2,722.7
International | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	72.0	180.6
Developed markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	2,445.5	4,496.0
Developed markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	63.1	102.2
Developed markets - repurchase agreements | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	(706.6)	(1,376.2)
Emerging markets | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	273.5	611.0
Emerging markets | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	21.0	51.6
Hedge funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	3,249.0	3,046.8
Hedge funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	294.9	275.4
Equity-like funds | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	4,014.1	3,816.4
Equity-like funds | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	332.8	317.8
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	1,470.8	2,166.8
Real estate | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	349.1	630.3
Real estate | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	21.6	36.2
Other | Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	1,261.7	1,143.6
Other | Retiree Health Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Line Items]
Fair value of plan assets	112.1	106.1
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	1,288.7	1,728.4
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	113.4	147.5
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	396.6	430.4
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	35.7	40.9
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	369.4	815.0
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	31.9	47.7
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	19.8	2.6
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	6.4	0.0
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	10.6	11.3
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	2.1
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	234.9	363.8
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	21.6	34.5
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	251.0	103.2
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	24.2	24.4
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	1,546.4	2,501.7
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	1,514.0	2,290.0
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	0.1	0.1
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	300.9	0.0
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	2,058.2	3,356.6
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	63.1	80.5
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	(713.0)	(1,376.2)
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	32.0	250.5
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	23.7
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	1,470.8	2,166.8
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	7.5
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	0.7
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	(131.8)	263.2
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	(19.9)	18.3
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	25.5	15.4
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	2.4	1.5
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	1.2
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	0.1
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	0.0
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	0.1
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	25.4	5.5
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	2.4	0.5
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	10.7
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	1.0
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	(2.1)
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	(0.1)
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	10,335.2	12,170.5
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	862.7	922.4
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	735.7	893.7
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	68.5	83.7
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	506.8	1,907.7
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	40.1	132.9
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	367.4	1,136.8
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	21.7
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	230.9	349.1
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	21.0	27.9
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	3,249.0	3,046.8
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	294.9	275.4
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	3,988.7	3,808.8
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	330.4	317.3
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	114.2	248.3
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	1,142.5	779.3
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	$ 107.8	$ 63.5