Pension and Other Postretirement Benefits (Details 4) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pooled Property Funds
Pension and Other Postretirement Benefits
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]		Fair Value Measured at Net Asset Value Per Share [Member]
Funds measured at NAV
Pension and Other Postretirement Benefits
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	Fair Value Measured at Net Asset Value Per Share [Member]
United Kingdom | Pension Plans
Pension and Other Postretirement Benefits
Fair value of plan assets	$ 505	$ 491	$ 418
United Kingdom | Pension Plans | Pooled Equity Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	122
United Kingdom | Pension Plans | Defined Benefit Plan, Cash [Member]
Pension and Other Postretirement Benefits
Fair value of plan assets		22
United Kingdom | Pension Plans | Pooled Target Return Funds
Pension and Other Postretirement Benefits
Fair value of plan assets		118
United Kingdom | Pension Plans | Fixed income: Pooled UK government index-linked securities
Pension and Other Postretirement Benefits
Fair value of plan assets		73
United Kingdom | Pension Plans | Fixed income: Pooled fixed income funds
Pension and Other Postretirement Benefits
Fair value of plan assets		88
United Kingdom | Pension Plans | Liability-driven investment funds
Pension and Other Postretirement Benefits
Fair value of plan assets	67	83
United Kingdom | Pension Plans | Pooled UK Government Securities Funds Index-Linked Securities
Pension and Other Postretirement Benefits
Fair value of plan assets	78
United Kingdom | Pension Plans | Pooled Global Debt Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	88
United Kingdom | Pension Plans | Pooled Diversified Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	52	55
United Kingdom | Pension Plans | Cash and Cash Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	15
United Kingdom | Pension Plans | Pooled Property Funds
Pension and Other Postretirement Benefits
Fair value of plan assets		52
United Kingdom | Pension Plans | Funds measured at NAV
Pension and Other Postretirement Benefits
Fair value of plan assets	83
United Kingdom | Pension Plans | Fair Value, Inputs, Level 1, 2 and 3
Pension and Other Postretirement Benefits
Fair value of plan assets	422	439
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1)
Pension and Other Postretirement Benefits
Fair value of plan assets	8	5
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1) | Pooled Equity Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1) | Defined Benefit Plan, Cash [Member]
Pension and Other Postretirement Benefits
Fair value of plan assets		5
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1) | Pooled Target Return Funds
Pension and Other Postretirement Benefits
Fair value of plan assets		0
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1) | Fixed income: Pooled UK government index-linked securities
Pension and Other Postretirement Benefits
Fair value of plan assets		0
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1) | Fixed income: Pooled fixed income funds
Pension and Other Postretirement Benefits
Fair value of plan assets		0
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1) | Liability-driven investment funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1) | Pooled UK Government Securities Funds Index-Linked Securities
Pension and Other Postretirement Benefits
Fair value of plan assets		0
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1) | Pooled Global Debt Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1) | Pooled Diversified Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
United Kingdom | Pension Plans | Quoted Prices in Active Markets (Level 1) | Cash and Cash Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	8
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2)
Pension and Other Postretirement Benefits
Fair value of plan assets	414	434
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2) | Pooled Equity Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	122
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2) | Defined Benefit Plan, Cash [Member]
Pension and Other Postretirement Benefits
Fair value of plan assets		17
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2) | Pooled Target Return Funds
Pension and Other Postretirement Benefits
Fair value of plan assets		118
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2) | Fixed income: Pooled UK government index-linked securities
Pension and Other Postretirement Benefits
Fair value of plan assets		73
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2) | Fixed income: Pooled fixed income funds
Pension and Other Postretirement Benefits
Fair value of plan assets		88
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2) | Liability-driven investment funds
Pension and Other Postretirement Benefits
Fair value of plan assets	67	83
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2) | Pooled UK Government Securities Funds Index-Linked Securities
Pension and Other Postretirement Benefits
Fair value of plan assets	78
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2) | Pooled Global Debt Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	88
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2) | Pooled Diversified Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	52	55
United Kingdom | Pension Plans | Significant Other Observable Inputs (Level 2) | Cash and Cash Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	7
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3)
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3) | Pooled Equity Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3) | Defined Benefit Plan, Cash [Member]
Pension and Other Postretirement Benefits
Fair value of plan assets		0
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3) | Pooled Target Return Funds
Pension and Other Postretirement Benefits
Fair value of plan assets		0
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3) | Fixed income: Pooled UK government index-linked securities
Pension and Other Postretirement Benefits
Fair value of plan assets		0
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3) | Fixed income: Pooled fixed income funds
Pension and Other Postretirement Benefits
Fair value of plan assets		0
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3) | Liability-driven investment funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3) | Pooled UK Government Securities Funds Index-Linked Securities
Pension and Other Postretirement Benefits
Fair value of plan assets		0
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3) | Pooled Global Debt Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3) | Pooled Diversified Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
United Kingdom | Pension Plans | Significant Unobservable Inputs (Level 3) | Cash and Cash Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0
North America | Pension Plans
Pension and Other Postretirement Benefits
Fair value of plan assets	830	846	$ 790
North America | Pension Plans | Cash and cash equivalents
Pension and Other Postretirement Benefits
Fair value of plan assets	14	30
North America | Pension Plans | Equity mutual funds: Index equity
Pension and Other Postretirement Benefits
Fair value of plan assets	157	134
North America | Pension Plans | Pooled Equity Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	34	30
North America | Pension Plans | Fixed income: Other
Pension and Other Postretirement Benefits
Fair value of plan assets	7	7
North America | Pension Plans | Fixed income: Government and agency securities
Pension and Other Postretirement Benefits
Fair value of plan assets	103	110
North America | Pension Plans | Fixed income: Corporate bonds and notes
Pension and Other Postretirement Benefits
Fair value of plan assets	460	499
North America | Pension Plans | Fixed income: U.S.Treasury bonds and notes
Pension and Other Postretirement Benefits
Fair value of plan assets	61	37
North America | Pension Plans | Accruals and payables—net
Pension and Other Postretirement Benefits
Fair value of plan assets	(6)
North America | Pension Plans | Accruals and payables—net
Pension and Other Postretirement Benefits
Fair value of plan assets		(1)
North America | Pension Plans | Fair Value, Inputs, Level 1, 2 and 3 | Defined Benefit Plan, Assets Before Receivables, Net
Pension and Other Postretirement Benefits
Fair value of plan assets	836	847
North America | Pension Plans | Quoted Prices in Active Markets (Level 1) | Defined Benefit Plan, Assets Before Receivables, Net
Pension and Other Postretirement Benefits
Fair value of plan assets	228	178
North America | Pension Plans | Quoted Prices in Active Markets (Level 1) | Cash and cash equivalents
Pension and Other Postretirement Benefits
Fair value of plan assets	10	7
North America | Pension Plans | Quoted Prices in Active Markets (Level 1) | Equity mutual funds: Index equity
Pension and Other Postretirement Benefits
Fair value of plan assets	157	134
North America | Pension Plans | Quoted Prices in Active Markets (Level 1) | Pooled Equity Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Quoted Prices in Active Markets (Level 1) | Fixed income: Other
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Quoted Prices in Active Markets (Level 1) | Fixed income: Government and agency securities
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Quoted Prices in Active Markets (Level 1) | Fixed income: Corporate bonds and notes
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Quoted Prices in Active Markets (Level 1) | Fixed income: U.S.Treasury bonds and notes
Pension and Other Postretirement Benefits
Fair value of plan assets	61	37
North America | Pension Plans | Significant Other Observable Inputs (Level 2) | Defined Benefit Plan, Assets Before Receivables, Net
Pension and Other Postretirement Benefits
Fair value of plan assets	608	669
North America | Pension Plans | Significant Other Observable Inputs (Level 2) | Cash and cash equivalents
Pension and Other Postretirement Benefits
Fair value of plan assets	4	23
North America | Pension Plans | Significant Other Observable Inputs (Level 2) | Equity mutual funds: Index equity
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Significant Other Observable Inputs (Level 2) | Pooled Equity Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	34	30
North America | Pension Plans | Significant Other Observable Inputs (Level 2) | Fixed income: Other
Pension and Other Postretirement Benefits
Fair value of plan assets	7	7
North America | Pension Plans | Significant Other Observable Inputs (Level 2) | Fixed income: Government and agency securities
Pension and Other Postretirement Benefits
Fair value of plan assets	103	110
North America | Pension Plans | Significant Other Observable Inputs (Level 2) | Fixed income: Corporate bonds and notes
Pension and Other Postretirement Benefits
Fair value of plan assets	460	499
North America | Pension Plans | Significant Other Observable Inputs (Level 2) | Fixed income: U.S.Treasury bonds and notes
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Significant Unobservable Inputs (Level 3) | Defined Benefit Plan, Assets Before Receivables, Net
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Significant Unobservable Inputs (Level 3) | Cash and cash equivalents
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Significant Unobservable Inputs (Level 3) | Equity mutual funds: Index equity
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Significant Unobservable Inputs (Level 3) | Pooled Equity Funds
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Significant Unobservable Inputs (Level 3) | Fixed income: Other
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Significant Unobservable Inputs (Level 3) | Fixed income: Government and agency securities
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Significant Unobservable Inputs (Level 3) | Fixed income: Corporate bonds and notes
Pension and Other Postretirement Benefits
Fair value of plan assets	0	0
North America | Pension Plans | Significant Unobservable Inputs (Level 3) | Fixed income: U.S.Treasury bonds and notes
Pension and Other Postretirement Benefits
Fair value of plan assets	$ 0	$ 0