Consolidated Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net Cash Provided by Operating Activities [Abstract]
Net Income (Loss) Attributable to Parent	$ 214	$ 250
Depreciation, Amortization and Accretion, Net	534	653
Provision for Loan Losses Expensed Including Discontinued Operations	271	220
Gain Loss on Sales of Loans Net Including Discontinued Operations	(14)	(1)
Availableforsale Securities Gross Realized Gain Loss Excluding Otti Including Disc Ops	(27)	(54)
Gain (Loss) on Extinguishment of Debt	1	4
Payments for Origination and Purchases of Loans Held-for-sale	(21)	(44)
Proceeds from Sale of Loans Held-for-sale	20	104
Increase (Decrease) in Deferred Income Taxes	91	147
Increase (Decrease) in Interest Payable, Net	31	24
Increase (Decrease) in Other Operating Assets	60	46
Increase (Decrease) in Other Operating Liabilities	(20)	(122)
Increase (Decrease) in Other Operating Assets and Liabilities, Net	35	(25)
Net cash provided by (used in) operating activities	1,175	1,202
Payments to Acquire Available-for-sale Securities	(2,833)	(4,870)
Proceeds from sales of available-for-sale securities	1,045	4,175
Proceeds from maturities and repayment of available-for-sale securities	589	409
Payments to Acquire Held-to-maturity Securities	(215)	(118)
Proceeds from Sale and Maturity of Held-to-maturity Securities	5	0
Payments for (Proceeds from) Loans and Leases	(405)	(1,402)
Proceeds from Sale of Loans Held-for-investment	1,164	2,594
Originations and repayments of loans held-for-investment and other	1,174	684
Purchases of operating lease assets	(893)	(701)
Disposals of operating lease assets	1,545	1,535
Increase (Decrease) in Restricted Cash	355	48
Increase (Decrease) in Non marketable equity securities	213	(315)
Payments for (Proceeds from) Other Investing Activities	(59)	(20)
Net cash provided by investing activities	(663)	651
Net Cash Used in Financing Activities [Abstract]
Proceeds from (Repayments of) Short-term Debt	(4,303)	(2,739)
Increase (Decrease) in Deposits	5,451	3,780
Proceeds from issuance of long-term debt	4,488	4,244
Repayments of long-term debt	(7,573)	(8,490)
Payments for Repurchase of Common Stock	(169)	(14)
Payments of Dividends	(38)	(15)
Net cash (used in) provided by financing activities	(2,144)	(3,234)
Effect of exchange-rate changes on cash and cash equivalents	0	2
Cash and Cash Equivalents, Period Increase (Decrease)	(1,632)	(1,379)
Cash and Cash Equivalents, at Carrying Value	5,934	6,380
Cash and Cash Equivalents, at Carrying Value	4,302	5,001
Supplemental Cash Flow Information [Abstract]
Interest Paid	648	626
Income Taxes Paid	2	0
Held-to-maturity securities received in consideration for loans sold	56	0
Transfer of Portfolio Loans and Leases to Held-for-sale	1,213	2,599
Proceeds from sales and repayments of mortgage loans held-for-investment originally designated as held-for-sale	$ 8	$ 9