Changes in Accumulated Other Comprehensive Loss - Tax Affect Of Foreign Currency Translation Adjustment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net translation on investments in foreign operations	$ 21	$ 5	$ (23)
Net hedges of investments in foreign operations	(41)	(14)
Net hedges of investments in foreign operations			40
Total tax impact	$ (20)	$ (9)	$ 17