Employee Retirement Plans (Details) - USD ($) $ in Millions		12 Months Ended
	Aug. 19, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation		$ 506	$ 466
Defined Benefit Plan, Benefit Obligation		(532)	(488)	$ (232)
Defined Benefit Plan, Plan Assets, Amount		355	332	107
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position		177	156
Defined Benefit Plan, Acquired and Established Plan Changes, Plan Assets		0	213
Defined Benefit Plan, Acquired and Established Plan Changes, Plan Assets		0	216
Defined Benefit Plan, Service Cost		19	15
Defined Benefit Plan, Interest Cost		5	5
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment		(5)	11
pension benefit obligation, benefits paid		(23)	(10)
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)		26	19
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)		2	7
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		22	0
Defined Benefit Plan, Plan Assets, Contributions by Employer		12	13
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant		2	2
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		14	(20)
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(23)	(10)
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)		16	19
Expense related to matching contributions		$ 102	$ 98	$ 87
Domestic Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Executive Retirement Plan Discount Rate		1.90%	2.94%
Executive Retirement Plan Rate of Compensation Increase		1.50%	1.50%
U.K. Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Assumptions used to Determine Expected Return		0.10%	0.60%
Executive Retirement Plan Discount Rate		0.10%	0.60%
Executive Retirement Plan Rate of Compensation Increase			3.00%
Other International Plans
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Assumptions used to Determine Expected Return		1.98%	2.05%
Executive Retirement Plan Discount Rate		0.67%	0.75%
Executive Retirement Plan Rate of Compensation Increase		2.40%	2.65%
Fair Value, Inputs, Level 3 [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)		$ 7
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)		1
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		15
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(9)
Other Contract
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount		223	$ 207
Other Contract | Fair Value, Inputs, Level 1 [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0	0
Other Contract | Fair Value, Inputs, Level 2 [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0	0
Other Contract | Fair Value, Inputs, Level 3 [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount		223	207
Defined Benefit Plan, Cash
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount			1
Defined Benefit Plan, Cash | Fair Value, Inputs, Level 1 [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount			1
Defined Benefit Plan, Cash | Fair Value, Inputs, Level 2 [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount			0
Defined Benefit Plan, Cash | Fair Value, Inputs, Level 3 [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount			0
Executive retirement plan [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation		54	50
Defined Benefit Plan, Benefit Obligation		(58)	(54)
Defined Benefit Plan, Plan Assets, Amount		0	0
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position		58	54
International retirement plans [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation		225	204
Defined Benefit Plan, Benefit Obligation		(247)	(223)
Defined Benefit Plan, Plan Assets, Amount		132	123
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position		115	100
U.K. Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Assets for Plan Benefits, Defined Benefit Plan	$ 213
Defined Benefit Plan, Accumulated Benefit Obligation		226	212
Defined Benefit Plan, Benefit Obligation	(216)	(226)	(212)
Defined Benefit Plan, Plan Assets, Amount		223	209
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ (3)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position		3	3
Executive Retirement Plan Discount Rate	0.40%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	0.40%
Executive Retirement Plan Rate of Compensation Increase	3.40%
U.K. Plan | Fair Value, Inputs, Level 1 [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0	1
U.K. Plan | Fair Value, Inputs, Level 2 [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0	0
U.K. Plan | Fair Value, Inputs, Level 3 [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Amount		$ 223	$ 207