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, 2018	$ 30,178	$ 3,817	$ 3,053	$ 6,849	$ 18,118	$ (1,715)	$ 56
Beginning balance (in shares) at Dec. 31, 2018		763,326
Add (Deduct):
Net income	1,683				1,678		5
OCI	596					596
Stock transactions:
Issued in connection with equity awards, net	(30)	$ 13		(43)
Issued in connection with equity awards, net (in shares)		2,684
Cash dividends declared on common stock	(619)				(619)
Cash dividends declared on preferred stock	(87)				(87)
Equity-based compensation expense	80			80
Other, net	(37)			3	(40)
Ending balance at Jun. 30, 2019	31,764	$ 3,830	3,053	6,889	19,050	(1,119)	61
Ending balance (in shares) at Jun. 30, 2019		766,010
Beginning balance at Mar. 31, 2019	30,883	$ 3,830	3,053	6,843	18,518	(1,421)	60
Beginning balance (in shares) at Mar. 31, 2019		765,920
Add (Deduct):
Net income	885				886		(1)
OCI	302					302
Stock transactions:
Issued in connection with equity awards, net	(2)			(2)
Issued in connection with equity awards, net (in shares)		90
Cash dividends declared on common stock	(310)				(310)
Cash dividends declared on preferred stock	(44)				(44)
Equity-based compensation expense	48			48
Other, net	2						2
Ending balance at Jun. 30, 2019	31,764	$ 3,830	3,053	6,889	19,050	(1,119)	61
Ending balance (in shares) at Jun. 30, 2019		766,010
Beginning balance at Dec. 31, 2019	$ 66,558	$ 6,711	5,102	35,609	19,806	(844)	174
Beginning balance (in shares) at Dec. 31, 2019	1,342,166	1,342,166
Ending balance at Mar. 31, 2020	$ 66,061	$ 6,737	4,599	35,584	18,076	898	167
Ending balance (in shares) at Mar. 31, 2020		1,347,461
Beginning balance at Dec. 31, 2019	$ 66,558	$ 6,711	5,102	35,609	19,806	(844)	174
Beginning balance (in shares) at Dec. 31, 2019	1,342,166	1,342,166
Add (Deduct):
Net income	$ 2,021				2,015		6
OCI	1,691					1,691
Stock transactions:
Issued in connection with equity awards, net	(84)	$ 27		(109)	(2)
Issued in connection with equity awards, net (in shares)		5,443
Issued in connection with preferred stock offering	2,544		2,544
Redemption of preferred stock	(503)		(503)
Cash dividends declared on common stock	(1,210)				(1,210)
Cash dividends declared on preferred stock	(127)				(127)
Equity-based compensation expense	176			176
Cumulative effect adjustment for new accounting standards	(2,109)				(2,109)
Other, net	(74)						(74)
Ending balance at Jun. 30, 2020	$ 68,883	$ 6,738	7,143	35,676	18,373	847	106
Ending balance (in shares) at Jun. 30, 2020	1,347,609	1,347,609
Beginning balance at Mar. 31, 2020	$ 66,061	$ 6,737	4,599	35,584	18,076	898	167
Beginning balance (in shares) at Mar. 31, 2020		1,347,461
Add (Deduct):
Net income	958				955		3
OCI	(51)					(51)
Stock transactions:
Issued in connection with equity awards, net	(4)	$ 1		(5)
Issued in connection with equity awards, net (in shares)		148
Issued in connection with preferred stock offering	2,544		2,544
Cash dividends declared on common stock	(605)				(605)
Cash dividends declared on preferred stock	(53)				(53)
Equity-based compensation expense	97			97
Other, net	(64)						(64)
Ending balance at Jun. 30, 2020	$ 68,883	$ 6,738	$ 7,143	$ 35,676	$ 18,373	$ 847	$ 106
Ending balance (in shares) at Jun. 30, 2020	1,347,609	1,347,609