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, 2017	$ 29,695	$ 3,910	$ 3,053	$ 7,893	$ 16,259	$ (1,467)	$ 47
Beginning balance (in shares) at Dec. 31, 2017		782,006
Add (Deduct):
Net income	1,613				1,607		6
OCI	(239)					(239)
Stock transactions:
Issued in connection with equity awards, net	(2)	$ 20		(22)
Issued in connection with equity awards, net (in shares)		4,055
Repurchase of common stock (in shares)		(11,614)
Repurchase of common stock	(630)	$ (58)		(572)
Cash dividends declared on common stock	(582)				(582)
Cash dividends declared on preferred stock	(87)				(87)
Equity-based compensation expense	76			76
Other, net	(12)			(11)			(1)
Ending balance at Jun. 30, 2018	29,832	$ 3,872	3,053	7,364	17,197	(1,706)	52
Ending balance (in shares) at Jun. 30, 2018		774,447
Beginning balance at Mar. 31, 2018	29,662	$ 3,899	3,053	7,593	16,712	(1,645)	50
Beginning balance (in shares) at Mar. 31, 2018		779,752
Add (Deduct):
Net income	822				819		3
OCI	(61)					(61)
Stock transactions:
Issued in connection with equity awards, net	11	$ 2		9
Issued in connection with equity awards, net (in shares)		456
Repurchase of common stock (in shares)		(5,761)
Repurchase of common stock	(310)	$ (29)		(281)
Cash dividends declared on common stock	(290)				(290)
Cash dividends declared on preferred stock	(44)				(44)
Equity-based compensation expense	45			45
Other, net	(3)			(2)			(1)
Ending balance at Jun. 30, 2018	29,832	$ 3,872	3,053	7,364	17,197	(1,706)	52
Ending balance (in shares) at Jun. 30, 2018		774,447
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	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	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	766,010