Consolidated Statements of Changes in Shareholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Preferred Stock	Additional Paid-In Capital	Retained Earnings	AOCI	Noncontrolling Interests
Beginning balance at Dec. 31, 2016	$ 29,926	$ 4,047	$ 3,053	$ 9,104	$ 14,809	$ (1,132)	$ 45
Beginning balance (in shares) at Dec. 31, 2016		809,475
Add (Deduct):
Net income	1,748				1,736		12
OCI	96					96
Stock transactions:
Issued in connection with equity awards, net	104	$ 37		67
Issued in connection with equity awards, net (in shares)		7,201
Repurchase of common stock	(1,240)	$ (139)		(1,101)
Repurchase of common stock (in shares)		(27,755)
Cash dividends declared on common stock	(747)				(747)
Cash dividends declared on preferred stock	(130)				(130)
Equity-based compensation expense	109			109
Other, net	(13)			13	(12)		(14)
Ending balance at Sep. 30, 2017	29,853	$ 3,945	3,053	8,192	15,656	(1,036)	43
Ending balance (in shares) at Sep. 30, 2017		788,921
Beginning balance at Dec. 31, 2017	$ 29,695	$ 3,910	3,053	7,893	16,259	(1,467)	47
Beginning balance (in shares) at Dec. 31, 2017	782,006	782,006
Add (Deduct):
Net income	$ 2,452				2,439		13
OCI	(385)					(385)
Stock transactions:
Issued in connection with equity awards, net	(1)	$ 21		(22)
Issued in connection with equity awards, net (in shares)		4,163
Repurchase of common stock	(830)	$ (78)		(752)
Repurchase of common stock (in shares)		(15,549)
Cash dividends declared on common stock	(895)				(895)
Cash dividends declared on preferred stock	(130)				(130)
Equity-based compensation expense	113			113
Other, net	(12)			(11)			(1)
Ending balance at Sep. 30, 2018	$ 30,007	$ 3,853	$ 3,053	$ 7,221	$ 17,673	$ (1,852)	$ 59
Ending balance (in shares) at Sep. 30, 2018	770,620	770,620