Computation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 775	$ 631	$ 1,520	$ 1,009
Weighted average number of common shares (in shares)	775,836	808,980	777,716	809,439
Effect of dilutive outstanding equity-based awards (in shares)	9,914	10,409	10,646	11,633
Weighted average number of diluted common shares (in shares)	785,750	819,389	788,362	821,072
Basic EPS (in dollars per share)	$ 1.00	$ 0.78	$ 1.95	$ 1.25
Diluted EPS (in dollars per share)	$ 0.99	$ 0.77	$ 1.93	$ 1.23
Anti-dilutive awards (in shares)	0	187	45	297