Computation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 789	$ 597	$ 2,309	$ 1,606
Weighted average number of common shares (in shares)	771,562	794,558	775,642	804,424
Effect of dilutive outstanding equity-based awards (in shares)	10,305	11,566	10,498	11,605
Weighted average number of diluted common shares (in shares)	781,867	806,124	786,140	816,029
Basic EPS (in dollars per share)	$ 1.02	$ 0.75	$ 2.98	$ 2.00
Diluted EPS (in dollars per share)	$ 1.01	$ 0.74	$ 2.94	$ 1.97
Anti-dilutive awards (in shares)	61	184	80	222