Earnings Per Share - Share Repurchase Activity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Stock repurchased (in shares)	48	72	39
Cost of Shares	$ 3,373	$ 4,671	$ 1,970
Average Price Paid per Share (in dollars per share)	$ 70.54	$ 64.64	$ 50.80