v3.20.2

Pension and Other Postretirement Benefits - Narrative (Details) $ in Millions		1 Months Ended	3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
	Jan. 01, 2020 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2020 USD ($) participants	Jun. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) participants	Sep. 30, 2020 USD ($) participants	Sep. 30, 2019 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jul. 31, 2020	Jun. 01, 2020 participants	Apr. 01, 2020 USD ($)	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Retirement plans, liability	$ 1,920
Retirement plans, current liability	60
Retirement plans, benefit obligation	4,255
Retirement plans, plan assets	2,335
Establishment of retirement plans, AOCI	$ 1,752					$ 50
Expected employer contributions, 2020			$ 280			280	$ 280
Liability, Defined Benefit Plan, Noncurrent													$ 15
asset, defined benefit plan													$ 65
Liability, Other Postretirement Defined Benefit Plan			7			7	7
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax			5
U.K. Defined Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement							250
Forecast
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost										$ 100
Service cost										$ 25
Payment for Pension and Other Postretirement Benefits									$ 20
Pension benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost			25		$ 1		119	$ 4
Service cost			6		1		16	2
Multiemployer contribution expense			0		16		0	46
Expected employer contributions, 2020			260			260	260
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		1.55%		1.55%										2.05%
Other postretirement benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost			5		0		17	0
Service cost			1		0		3	0
Multiemployer contribution expense			0		$ 4		0	$ 15
Expected employer contributions, 2020			55			55	55
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate											2.54%			3.17%
Other Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions, 2020			10			10	10
U.K. Defined Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Retirement plans, benefit obligation			240			240	240
Retirement plans, plan assets			$ 260			$ 260	$ 260
Defined Benefit Plan, Participants | participants			1,050			1,050	1,050					1,800
Defined Benefit Plan, Plan Assets, Contributions by Employer				$ 10
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement			$ 3				$ 58
U.K. Defined Benefit Plan [Member] | ParentCo
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Participants | participants												3,350
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement		$ 400
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Assets Transferred to (from) Plan		$ 460

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