Computation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 749	$ 745
Weighted average number of common shares (in shares)	764,135	779,617
Effect of dilutive outstanding equity-based awards (in shares)	9,936	11,388
Weighted average number of diluted common shares (in shares)	774,071	791,005
Basic EPS (in dollars per share)	$ 0.98	$ 0.96
Diluted EPS (in dollars per share)	$ 0.97	$ 0.94
Anti-dilutive awards (in shares)	0	90