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, 2014	$ 24,377	$ 3,603	$ 2,603	$ 6,517	$ 12,317	$ (751)	$ 88
Beginning balance (in shares) at Dec. 31, 2014		720,698
Add (Deduct):
Net Income	1,581				1,545		36
Net change in AOCI	(45)					(45)
Stock transactions:
Issued in business combinations	2,188	$ 270		1,918
Issued in business combinations (in shares)		54,000
Issued in connection with equity awards	110	$ 34		76
Issued in connection with equity awards (in shares)		6,785
Shares repurchased	(51)	$ (6)		(45)
Shares repurchased (in shares)		(1,333)
Excess tax benefits in connection with equity awards	9			9
Issued in connection with preferred stock offerings	0
Purchase of additional ownership of AmRisc LP	(222)			(219)			(3)
Cash dividends declared on common stock	(579)				(579)
Cash dividends declared on preferred stock	(111)				(111)
Equity-based compensation expense	88			88
Other, net	(81)						(81)
Ending balance at Sep. 30, 2015	27,264	$ 3,901	2,603	8,344	13,172	(796)	40
Ending balance (in shares) at Sep. 30, 2015		780,150
Beginning balance at Dec. 31, 2015	$ 27,340	$ 3,902	2,603	8,365	13,464	(1,028)	34
Beginning balance (in shares) at Dec. 31, 2015	780,337	780,337
Add (Deduct):
Net Income	$ 1,799				1,790		9
Net change in AOCI	278					278
Stock transactions:
Issued in business combinations	1,063	$ 158		905
Issued in business combinations (in shares)		31,666
Issued in connection with equity awards	57	$ 23		34
Issued in connection with equity awards (in shares)		4,735
Shares repurchased	(193)	$ (26)		(167)
Shares repurchased (in shares)		(5,314)
Issued in connection with preferred stock offerings	450		450
Cash dividends declared on common stock	(682)				(682)
Cash dividends declared on preferred stock	(123)				(123)
Equity-based compensation expense	96			96
Other, net	6			0	10		(4)
Ending balance at Sep. 30, 2016	$ 30,091	$ 4,057	$ 3,053	$ 9,233	$ 14,459	$ (750)	$ 39
Ending balance (in shares) at Sep. 30, 2016	811,424	811,424