Computation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 842	$ 775	$ 1,591	$ 1,520
Weighted average number of common shares (in shares)	765,958	775,836	765,052	777,716
Effect of dilutive outstanding equity-based awards (in shares)	8,645	9,914	9,277	10,646
Weighted average number of diluted common shares (in shares)	774,603	785,750	774,329	788,362
Basic EPS (in dollars per share)	$ 1.10	$ 1.00	$ 2.08	$ 1.95
Diluted EPS (in dollars per share)	$ 1.09	$ 0.99	$ 2.06	$ 1.93
Anti-dilutive awards (in shares)	26	0	18	45