Income Taxes - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income tax expense	$ 3,000,000	$ 0	$ 12,000,000	$ 26,000,000
Net discrete (benefit) expense related to changes in valuation allowance	$ 0	$ (2,000,000)	$ 0	$ 17,000,000