Income Taxes - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Mar. 31, 2020
Income Taxes [Line Items]
Income tax expense (benefit)	$ 27,000,000	$ (186,000,000)	$ 42,000,000	$ 63,000,000
Income (loss) before income taxes	98,000,000	(889,000,000)	131,000,000	(1,257,000,000)
Net discrete tax adjustments	$ 2,000,000	2,000,000	$ 29,000,000	293,000,000
U.S. statutory rate	21.00%		21.00%
Non-cash goodwill impairment charge		$ 182,000,000		$ 182,000,000
Deferred tax asset, tax credit carryforwards, foreign	$ 150,000,000		$ 150,000,000		$ 133,000,000
Foreign Tax Authority
Income Taxes [Line Items]
Income tax expense (benefit)			0
Tax credit carryforward, valuation allowance	328,000,000		328,000,000			$ 295,000,000
Valuation allowance	1,100,000,000		1,100,000,000		1,100,000,000
Deferred tax assets	1,400,000,000		$ 1,400,000,000		1,300,000,000
Foreign Tax Authority | Luxembourg
Income Taxes [Line Items]
Valuation allowance					933,000,000
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			2031
Domestic and State and Local Authority
Income Taxes [Line Items]
Net deferred tax assets	800,000,000		$ 800,000,000		$ 1,200,000,000
Net deferred tax assets, unlimited lives	500,000,000		500,000,000
Net deferred tax assets, limited lives	300,000,000		$ 300,000,000
Net deferred tax assets, expiration period			between 2025 and 2041
Valuation allowance	$ 368,000,000		$ 368,000,000