Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Cash Flows From Operations
Net income	$ 156.7	$ 17.0	$ 336.6	$ 163.0
Adjustments to reconcile net income to net cash flows from operations:
Provision for credit losses			54.1	127.4
Net depreciation, amortization and (accretion)			200.4	402.1
Net gains on asset sales and impairments on assets held for sale and other			(253.6)	(43.4)
Loss on debt extinguishment			203.8	0.0
Provision for deferred income taxes			111.0	87.9
Decrease in loans held for sale			80.3	244.3
Goodwill and intangible assets - impairment			0.0	4.2
Net (payment) reimbursement of expense from FDIC			(3.8)	4.4
Decrease (increase) in other assets			130.1	(37.0)
(Decrease) increase in other liabilities			(636.6)	42.4
Net cash flows provided by operations			222.3	995.3
Cash Flows From Investing Activities
Changes in loans, net			758.9	94.5
Purchases of investment securities			(3,339.0)	(1,855.2)
Proceeds from maturities of investment securities			2,215.2	1,624.1
Proceeds from asset and receivable sales			677.4	784.4
Net proceeds from sale of commercial air			10,004.0	0.0
Purchases of assets to be leased and other equipment			(604.2)	(935.8)
Net decrease in short-term factoring receivables			(91.4)	(129.1)
Purchases of restricted stock			(4.8)	0.0
Proceeds from redemption of restricted stock			8.6	2.2
Payments to the FDIC under loss share agreements			(0.1)	(2.1)
Proceeds from the FDIC under loss share agreements and participation agreements			43.4	59.8
Proceeds from sale of OREO, net of repurchases			51.4	72.7
Net change in restricted cash			600.3	26.7
Net cash flows provided by (used in) investing activities			10,319.7	(257.8)
Cash Flows From Financing Activities
Proceeds from the issuance of term debt			16.8	8.5
Repayments of term debt and net settlements			(7,387.3)	(915.3)
Proceeds from FHLB advances			0.0	1,645.5
Repayments of FHLB advances			(15.4)	(1,768.0)
Net (decrease) increase in deposits			(1,360.8)	102.6
Collection of security deposits and maintenance funds			63.8	168.5
Use of security deposits and maintenance funds			(34.2)	(58.3)
Repurchase of common stock			(3,306.0)	0.0
Net proceeds from issuance of preferred stock			318.0	0.0
Dividends paid			(61.7)	(61.5)
Taxes paid through withholding of common stock under employee stock plans			(18.9)	(15.6)
Payments on affordable housing investment credits			(12.1)	(8.1)
Net cash flows used in financing activities			(11,797.8)	(901.7)
Effect of exchange rate changes on cash and cash equivalents			10.0	(2.3)
Decrease in unrestricted cash and cash equivalents			(1,245.8)	(166.5)
Unrestricted cash and cash equivalents, beginning of period			6,375.2	7,470.6	$ 7,470.6
Unrestricted cash and cash equivalents, end of period	5,129.4	7,304.1	5,129.4	7,304.1	$ 6,375.2
Supplementary Cash Flow Disclosure
Interest paid			(561.0)	(581.3)
Federal, foreign, state and local income taxes paid, net			(13.8)	(6.4)
Supplementary Non Cash Flow Disclosure
Transfer of assets from held for investment to held for sale			1,220.0	1,528.3
Transfer of assets from held for sale to held for investment			88.2	76.8
Deposits on flight equipment purchases applied to acquisition of flight equipment purchases, and origination of finance leases, capitalized interest, and buyer furnished equipment			91.2	179.9
Transfers of assets from held for investment to OREO			61.6	45.3
Capital lease unexercised bargain purchase options			17.5	7.1
Unfunded payments on affordable housing investment credits committed during the period	$ 50.1	$ 0.0	$ 50.1	$ 0.0