Stockholders' Equity - Share Repurchase Program (Details) - USD ($) shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jan. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Remaining authorized repurchase amount	$ 12,280,000,000		$ 12,280,000,000			$ 4,900,000,000
Share repurchase program, authorized amount					$ 10,000,000,000.0
Shares repurchased and retired (in shares)			13
Shares repurchased and retired	$ 1,379,000,000	$ 1,125,000,000	$ 2,621,000,000	$ 1,647,000,000