Common Stock (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Nov. 30, 2016
Equity, Class of Treasury Stock [Line Items]
Payments for repurchase of common stock	$ 300,000,000	$ 675,000,000
Stock-based compensation, shares issued during period	4,200,000	3,000,000.0
Common Stock
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased (in shares)	3,100,000	8,200,000
Payments for repurchase of common stock	$ 300,000,000	$ 675,000,000
Share repurchases program, authorized amount (up to)			$ 2,500,000,000
Stock repurchase program, remaining authorized repurchase amount	$ 566,000,000