Consolidated Balance Sheets - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deposits	$ 52,621	$ 53,236
Current Fiscal Year End Date	--12-31
Held-to-maturity Securities, Fair Value	$ 762
Preferred Stock, Shares Authorized	4,400	4,400
Common Stock, Shares Authorized	350,000	350,000
Common Stock, Shares, Issued	197,532	203,085
Common stock, outstanding shares	197,532	203,085
ASSETS
Cash and due from banks	$ 548	$ 737
Money market investments:
Interest-bearing deposits	782	1,411
Federal funds sold and security resell agreements	514	568
Investment securities:
Available-for-sale, at fair value	15,161	13,372
Trading account, at fair value	148	115
Marketable Securities	16,079	14,355
Loans held for sale	44	172
Loans, net of allowance
Loans and leases, net of unearned income and fees	44,780	42,649
Less allowance for loan losses	518	567
Loans, net of allowance	44,262	42,082
Other noninterest-bearing investments	1,029	884
Premises, equipment and software net	1,094	1,020
Goodwill	1,014	1,014
Core deposit and other intangibles	2	8
Other real estate owned	4	4
Other assets	916	984
Total assets	66,288	63,239
LIABILITIES AND SHAREHOLDERS' EQUITY
Noninterest-bearing demand	23,886	24,115
Interest-bearing:
Savings and Money Market	25,620	26,364
Time	3,115	2,757
Federal funds and other short-term borrowings	4,976	827
Long-term debt	383	535
Reserve for unfunded lending commitments	58	65
Other liabilities	571	942
Total liabilities	58,609	55,605
Shareholders' equity:
Preferred stock, without par value, authorized 4,400 shares	566	710
Common stock, without par value; authorized 350,000 shares; issued and outstanding 197,532 and 203,085 shares	4,445	4,725
Retained earnings	2,807	2,321
Accumulated Other Comprehensive Income (Loss)	139	122
Total shareholders' equity	7,679	7,634
Total liabilities and shareholders' equity	66,288	63,239
Fair Value, Inputs, Level 2 [Member]
Investment securities:
Trading account, at fair value	148	115
Estimate of Fair Value Measurement [Member]
Loans, net of allowance
Loans, net of allowance		42,111
Interest-bearing:
Time		2,744
Long-term debt		552
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Held-to-maturity Securities, Fair Value	762	$ 850
Interest-bearing:
Time	3,099
Long-term debt	$ 402