Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Valuation Allowance [Line Items]
Total income tax expense	$ 3	$ (407)	$ (520)	$ (715)
Effective income tax rate	(0.30%)	24.50%	16.70%	26.40%