Common Stock (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Nov. 30, 2019
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased (in shares)		0
Purchase of treasury shares	$ 445,000,000
Payments for repurchase of common stock	$ 434,000,000	$ 0
Stock-based compensation, shares issued during period (in shares)	2,600,000	2,800,000
Common Stock
Equity, Class of Treasury Stock [Line Items]
Share repurchases program, authorized amount (up to)			$ 2,500,000,000
Common stock repurchased (in shares)	3,400,000
Stock repurchase program, remaining authorized repurchase amount	$ 2,000,000,000