Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
OPERATING ACTIVITIES
Net income	$ 541	$ 521	$ 393
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	46	79	144
(Benefit) provision for deferred income taxes	(20)	158	79
Depreciation and amortization	122	133	122
Net periodic defined benefit cost	88	81	53
Share-based compensation expense	35	37	37
Net amortization of securities	23	48	39
Accretion of loan purchase discount	(49)	(71)	(53)
Net securities losses (gains)	1	(12)	(14)
Net loss/writedown on foreclosed property	4	0	13
Excess tax benefits from share-based compensation arrangements	(3)	(1)	(1)
Net change in trading securities	6	1	3
Net change in accrued income receivable	7	5	(8)
Net change in accrued expenses payable	38	35	59
Other, net	(3)	(342)	(70)
Net cash provided by operating activities	836	672	796
INVESTING ACTIVITIES
Maturities and redemptions of investment securities available-for-sale	2,849	3,839	2,779
Purchases of investment securities available-for-sale	(2,225)	(4,032)	(4,453)
Sales of investment securities available-for-sale	0	0	784
Net change in loans	549	(3,498)	(695)
Cash and cash equivalents acquired in acquisition of Sterling Bancshares, Inc.	0	0	721
Sales of Federal Home Loan Bank stock	(41)	(3)	(36)
Purchases of Federal Reserve Bank stock	0	0	26
Proceeds from sales of indirect private equity and venture capital funds	0	1	33
Proceeds from sales of foreclosed property	55	82	106
Net increase in premises and equipment	(102)	(55)	(121)
Other, net	7	4	(13)
Net cash provided by (used in) investing activities	1,174	(3,656)	(849)
FINANCING ACTIVITIES
Net change in deposits	1,229	4,520	3,296
Net change in short-term borrowings	143	40	(82)
Maturities and redemptions of medium- and long-term debt	(1,080)	(193)	(1,517)
Repurchases of common stock	(291)	(308)	(116)
Cash dividends paid on common stock	(123)	(97)	(73)
Issuances of common stock under employee stock plans	33	3	4
Excess tax benefits from share-based compensation arrangements	3	1	1
Other, net	(7)	(4)	13
Net cash (used in) provided by financing activities	(93)	3,962	1,526
Net increase in cash and cash equivalents	1,917	978	1,473
Cash and cash equivalents at beginning of period	4,534	3,556	2,083
Cash and cash equivalents at end of period	6,451	4,534	3,556
Interest paid	114	135	151
Income taxes, tax deposits and tax-related interest paid	115	46	73
Loans transferred to other real estate	14	42	69
Net noncash assets acquired in stock acquisition of Sterling Bancshares, Inc.	$ 0	$ 0	$ 82