Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Effective income tax rate reconciliation, percent	21.60%	23.70%	23.50%	24.10%
Discrete tax expense (benefit)	$ (21)	$ (37)
Discrete tax expense (benefit), foreign tax credits	(7)	$ 22
Discrete tax expense (benefit) related to excess tax benefits from stock based compensation			$ 16	$ 6
Potential decrease in unrecognized tax benefits	$ 55		$ 55