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	2,415				2,394		21
OCI	(88)					(88)
Stock transactions:
Issued in business combination	0
Issued in connection with equity awards, net	$ 120	$ 41		79
Issued in connection with equity awards, net (in shares)		8,059
Repurchase of common stock (in shares)	(35,500)	(35,528)
Repurchase of common stock	$ (1,613)	$ (178)		(1,435)
Cash dividends declared on common stock	(1,005)				(1,005)
Cash dividends declared on preferred stock	(174)				(174)
Equity-based compensation expense	132			132
Reclassification of certain tax effects					247	(247)
Other, net	(18)			13	(12)		(19)
Ending balance at Dec. 31, 2017	29,695	$ 3,910	3,053	7,893	16,259	(1,467)	47
Ending balance (in shares) at Dec. 31, 2017		782,006
Add (Deduct):
Net income	3,257				3,237		20
OCI	(248)					(248)
Stock transactions:
Issued in business combination	0
Issued in connection with equity awards, net	$ (6)	$ 23		(29)
Issued in connection with equity awards, net (in shares)		4,554
Repurchase of common stock (in shares)	(23,200)	(23,234)
Repurchase of common stock	$ (1,205)	$ (116)		(1,089)
Cash dividends declared on common stock	(1,204)				(1,204)
Cash dividends declared on preferred stock	(174)				(174)
Equity-based compensation expense	141			141
Other, net	(78)			(67)			(11)
Ending balance at Dec. 31, 2018	$ 30,178	$ 3,817	3,053	6,849	18,118	(1,715)	56
Ending balance (in shares) at Dec. 31, 2018	763,326	763,326
Add (Deduct):
Net income	$ 3,237				3,224		13
OCI	871					871
Stock transactions:
Issued in business combination	33,546	$ 2,875	2,045	28,626
Issued in business combinations (in shares)		575,067
Issued in connection with equity awards, net	(15)	$ 19		(34)
Issued in connection with equity awards, net (in shares)		3,773
Issued in connection with preferred stock offering	1,683		1,683
Redemption of preferred stock	(1,725)		(1,679)		(46)
Cash dividends declared on common stock	(1,309)				(1,309)
Cash dividends declared on preferred stock	(150)				(150)
Equity-based compensation expense	165			165
Other, net	77			3	(31)		105
Ending balance at Dec. 31, 2019	$ 66,558	$ 6,711	$ 5,102	$ 35,609	$ 19,806	$ (844)	$ 174
Ending balance (in shares) at Dec. 31, 2019	1,342,166	1,342,166