Income Taxes - Recognition of Uncertain Tax Positions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Tax benefits, that if recognized, would affect the effective tax rate	$ 141	$ 134	$ 108
Income tax expense for accrued interest	$ 1	$ 2	$ 0