Shareholders' Equity - Additional Information (Details) - USD ($)	3 Months Ended		96 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Feb. 28, 2017	Nov. 30, 2014	Apr. 30, 2012
Equity, Class of Treasury Stock [Line Items]
Total cost of shares purchased	$ 463,000,000	$ 101,000,000
Number of shares excluded from the calculation of diluted earnings per share (in shares)	0	100,000
2012 - Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Share repurchase authorization limit (up to)	$ 15,000,000,000.0		$ 15,000,000,000.0	$ 5,000,000,000.0	$ 5,000,000,000.0	$ 5,000,000,000.0
Share repurchase, remaining authorization limit (in shares)	$ 1,600,000,000		$ 1,600,000,000
Shares purchased (in shares)	2,200,000	600,000	130,900,000
Total cost of shares purchased	$ 461,000,000	$ 100,000,000	$ 13,400,000,000