Income Taxes - Narrative (Details) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) Installment	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Income Taxes [Line Items]
Income tax expense (benefit)	$ (13)		$ 31		$ 50	$ 63
Income (loss) before income taxes	$ (10)		121		(1,267)	165
Net discrete tax adjustments			$ (6)		$ 278	$ 7
U.S. statutory rate	21.00%		21.00%		21.00%	21.00%
Non-cash goodwill impairment charge		$ 182
Deferred tax asset, tax credit carryforwards, foreign	$ 123				$ 123		$ 403
CARES act of 2020, net operating loss carryback period					5 years
CARES Act Of 2020 refundable alternative minimum tax credit carryforwards	5
Number of equal annual installments to receive refund alternative minimum tax credit carryforwards | Installment					2
England
Income Taxes [Line Items]
Change in enacted tax rate, amount	(14)
Luxembourg
Income Taxes [Line Items]
Change in enacted tax rate, amount				$ 6
Foreign Tax Authority
Income Taxes [Line Items]
Tax credit carryforward, valuation allowance	298	$ 295			$ 298		3
Valuation allowance	1,000				$ 1,000		1,000
Tax credit carryforward expiration period					through 2024 and a portion of those expiring in 2025
Deferred tax assets	1,300				$ 1,300		$ 1,200
Foreign Tax Authority | Beginning Year
Income Taxes [Line Items]
Tax credit carryforward expiration year					2025
Foreign Tax Authority | Ending Year
Income Taxes [Line Items]
Tax credit carryforward expiration year					2030
Foreign Tax Authority | Luxembourg
Income Taxes [Line Items]
Valuation allowance	924				$ 924
Domestic and State and Local Authority
Income Taxes [Line Items]
Net deferred tax assets	1,200				1,200
Net deferred tax assets, unlimited lives	1,000				1,000
Net deferred tax assets, limited lives	250				$ 250
Net deferred tax assets, expiration period					between 2025 and 2040
Valuation allowance	$ 308				$ 308