Condensed Consolidated Statement of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net Income (Loss) Attributable to Parent	$ 748	$ 819
Depreciation, Amortization and Accretion, Net	1,434	1,807
Provision for Loan Losses Expensed Including Discontinued Operations	854	650
Gain Loss on Sales of Loans Net Including Discontinued Operations	65	4
Availableforsale Securities Gross Realized Gain Loss Excluding Otti Including Disc Ops	(73)	(145)
Gain (Loss) on Extinguishment of Debt	(6)	(4)
Payments for Origination and Purchases of Loans Held-for-sale	252	141
Proceeds from Sale of Loans Held-for-sale	236	184
Increase (Decrease) in Deferred Income Taxes	(289)	(322)
Increase (Decrease) in Interest Payable, Net	202	112
Increase (Decrease) in Other Operating Assets	57	(16)
Increase (Decrease) in Other Operating Liabilities	(19)	(65)
Increase (Decrease) in Other Operating Assets and Liabilities, Net	(70)	(30)
Net Cash Provided by (Used in) Operating Activities	3,373	3,589
Net Cash (Used in) Provided by Investing Activities [Abstract]
Payments to Acquire Available-for-sale Securities	(9,022)	(11,027)
Proceeds from sales of available-for-sale securities	2,926	8,546
Proceeds from maturities and repayment of available-for-sale securities	2,002	2,411
Payments to Acquire Held-to-maturity Securities	(709)	(650)
Proceeds from Sale and Maturity of Held-to-maturity Securities	32	0
Payments for (Proceeds from) Loans and Leases	(3,125)	(2,924)
Proceeds from Sale of Loans Held-for-investment	1,323	4,221
Originations and repayments of loans held-for-investment and other	(1,021)	5,384
Purchases of operating lease assets	(2,844)	(2,360)
Disposals of operating lease assets	4,409	4,631
Payments to Acquire Interest in Subsidiaries and Affiliates	0	309
Increase (Decrease) in Restricted Cash	497	622
Increase (Decrease) in Non marketable equity securities	(20)	(401)
Payments for (Proceeds from) Other Investing Activities	(159)	(157)
Net cash provided by investing activities	(3,669)	(2,781)
Net Cash Used in Financing Activities [Abstract]
Proceeds from (Repayments of) Short-term Debt	(2,500)	(1,673)
Increase (Decrease) in Deposits	11,050	9,240
Proceeds from issuance of long-term debt	13,302	11,229
Repayments of long-term debt	(22,376)	(20,758)
Payments for Repurchase of Preferred Stock and Preference Stock	0	696
Payments for Repurchase of Common Stock	(563)	(173)
Payments of Dividends	(130)	(70)
Net cash (used in) provided by financing activities	(1,217)	(2,901)
Effect of exchange-rate changes on cash and cash equivalents	3	2
Cash and Cash Equivalents, Period Increase (Decrease)	(1,510)	(2,091)
Cash and Cash Equivalents, at Carrying Value	5,934	6,380
Cash and Cash Equivalents, at Carrying Value	4,424	4,289
Supplemental Cash Flow Information [Abstract]
Interest Paid	1,910	1,860
Income Taxes Paid	32	16
Held-to-maturity securities received in consideration for loans sold	56	0
Transfer of Portfolio Loans and Leases to Held-for-sale	1,326	4,231
Proceeds from sales and repayments of mortgage loans held-for-investment originally designated as held-for-sale	$ 29	$ 28