Parent and Guarantor Consolidating Financial Statements (Schedule of Condensed Consolidating Statement of Cash Flows) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 4,567	$ 5,111	$ 3,403
Payments to Acquire Available-for-sale Securities	(16,031)	(12,250)	(5,417)
Proceeds from sales of available-for-sale securities	11,036	6,874	4,260
Proceeds from maturities and repayment of available-for-sale securities	3,379	4,255	2,657
Payments to Acquire Held-to-maturity Securities	(841)	0	0
Payments to Acquire Loans Held-for-investment	3,859	4,501	877
Proceeds from Sale of Loans Held-for-sale	4,285	3,197	2,592
Originations and repayments of loans held-for-investment and other	(8,826)	(9,344)	(4,147)
Purchases of operating lease assets	(3,274)	(4,685)	(9,884)
Disposals of operating lease assets	6,304	5,546	5,860
Payments to Acquire Interest in Subsidiaries and Affiliates	(309)	0	0
Capital contributions to subsidiaries	0	0	0
Returns of contributed capital	0	0	0
Proceeds from Divestiture of Businesses	0	1,049	47
Increase (Decrease) in Restricted Cash	392	264	1,625
Increase (Decrease) in Non marketable equity securities	(628)	(147)	66
Payments for (Proceeds from) Other Investing Activities	(312)	(5)	6
Net cash provided by investing activities	(8,684)	(9,747)	(3,212)
Proceeds from (Repayments of) Short-term Debt	4,564	1,028	(1,494)
Increase (Decrease) in Deposits	12,508	8,247	4,851
Proceeds from issuance of long-term debt	14,155	30,665	27,192
Repayments of long-term debt	(26,412)	(31,350)	(30,426)
Net Change in Debt, Intercompany	0	0	0
Payments for Repurchase of Redeemable Preferred Stock	(696)	(559)	0
Payments for Repurchase of Common Stock	(341)	(16)	0
Payments of Dividends	(108)	(2,571)	(268)
Dividends paid and returns of contributed capital, Intercompany	0	0	0
Capital contributions from parent	0	0	0
Net cash (used in) provided by financing activities	3,670	5,444	(145)
Effect of exchange-rate changes on cash and cash equivalents	1	(4)	(1)
Cash and Cash Equivalents, Period Increase (Decrease)	(446)	804	45
Cash and Cash Equivalents, at Carrying Value	6,380	5,576	5,531
Cash and Cash Equivalents, at Carrying Value	5,934	6,380	5,576
Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	241	370	330
Payments to Acquire Available-for-sale Securities	0	0	0
Proceeds from sales of available-for-sale securities	0	0	0
Proceeds from maturities and repayment of available-for-sale securities	0	0	0
Payments to Acquire Held-to-maturity Securities	0
Payments to Acquire Loans Held-for-investment	4	169	0
Proceeds from Sale of Loans Held-for-sale	0	0	0
Originations and repayments of loans held-for-investment and other	2,013	1,954	1,900
Purchases of operating lease assets	0	(94)	(2,337)
Disposals of operating lease assets	25	7	3,053
Payments to Acquire Interest in Subsidiaries and Affiliates	(309)
Capital contributions to subsidiaries	(3,908)	(796)	(1,179)
Returns of contributed capital	3,678	1,444	1,422
Proceeds from Divestiture of Businesses		1,049	46
Increase (Decrease) in Restricted Cash	(120)	(7)	0
Increase (Decrease) in Non marketable equity securities	0	0	0
Payments for (Proceeds from) Other Investing Activities	(206)	(47)	(29)
Net cash provided by investing activities	2,046	3,581	4,304
Proceeds from (Repayments of) Short-term Debt	169	115	113
Increase (Decrease) in Deposits	(61)	(91)	(121)
Proceeds from issuance of long-term debt	979	5,428	3,132
Repayments of long-term debt	(2,662)	(5,931)	(8,186)
Net Change in Debt, Intercompany	(382)	(977)	52
Payments for Repurchase of Redeemable Preferred Stock	(696)	(559)
Payments for Repurchase of Common Stock	(341)	(16)
Payments of Dividends	(108)	(2,571)	(268)
Dividends paid and returns of contributed capital, Intercompany	0	0	0
Capital contributions from parent	0	0	0
Net cash (used in) provided by financing activities	(3,102)	(4,602)	(5,278)
Effect of exchange-rate changes on cash and cash equivalents	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	(815)	(651)	(644)
Cash and Cash Equivalents, at Carrying Value	1,635	2,286	2,930
Cash and Cash Equivalents, at Carrying Value	820	1,635	2,286
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	6	525	1,789
Payments to Acquire Available-for-sale Securities	0	0	0
Proceeds from sales of available-for-sale securities	0	0	0
Proceeds from maturities and repayment of available-for-sale securities	0	0	0
Payments to Acquire Held-to-maturity Securities	0
Payments to Acquire Loans Held-for-investment	0	0	0
Proceeds from Sale of Loans Held-for-sale	0	0	0
Originations and repayments of loans held-for-investment and other	0	0	0
Purchases of operating lease assets	0	0	0
Disposals of operating lease assets	0	0	0
Payments to Acquire Interest in Subsidiaries and Affiliates	0
Capital contributions to subsidiaries	0	(1)	0
Returns of contributed capital	8	0	0
Proceeds from Divestiture of Businesses		0	0
Increase (Decrease) in Restricted Cash	0	0	0
Increase (Decrease) in Non marketable equity securities	0	0	0
Payments for (Proceeds from) Other Investing Activities	0	0	0
Net cash provided by investing activities	8	(1)	0
Proceeds from (Repayments of) Short-term Debt	0	0	0
Increase (Decrease) in Deposits	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Repayments of long-term debt	0	0	0
Net Change in Debt, Intercompany	0	0	0
Payments for Repurchase of Redeemable Preferred Stock	0	0
Payments for Repurchase of Common Stock	0	0
Payments of Dividends	0	0	0
Dividends paid and returns of contributed capital, Intercompany	(14)	(525)	(1,826)
Capital contributions from parent	0	1	0
Net cash (used in) provided by financing activities	(14)	(524)	(1,826)
Effect of exchange-rate changes on cash and cash equivalents	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	0	0	(37)
Cash and Cash Equivalents, at Carrying Value	0	0	37
Cash and Cash Equivalents, at Carrying Value	0	0	0
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	5,383	6,390	5,533
Payments to Acquire Available-for-sale Securities	(16,031)	(12,250)	(5,417)
Proceeds from sales of available-for-sale securities	11,036	6,874	4,277
Proceeds from maturities and repayment of available-for-sale securities	3,379	4,255	2,657
Payments to Acquire Held-to-maturity Securities	(841)
Payments to Acquire Loans Held-for-investment	3,855	4,332	894
Proceeds from Sale of Loans Held-for-sale	4,285	3,197	2,592
Originations and repayments of loans held-for-investment and other	(10,839)	(11,298)	(6,047)
Purchases of operating lease assets	(3,274)	(4,591)	(7,547)
Disposals of operating lease assets	6,279	5,539	2,807
Payments to Acquire Interest in Subsidiaries and Affiliates	0
Capital contributions to subsidiaries	0	0	0
Returns of contributed capital	0	0	0
Proceeds from Divestiture of Businesses		0	1
Increase (Decrease) in Restricted Cash	512	271	1,625
Increase (Decrease) in Non marketable equity securities	(628)	(147)	66
Payments for (Proceeds from) Other Investing Activities	(197)	42	35
Net cash provided by investing activities	(10,241)	(11,229)	(5,691)
Proceeds from (Repayments of) Short-term Debt	4,395	913	(1,607)
Increase (Decrease) in Deposits	12,569	8,338	4,972
Proceeds from issuance of long-term debt	13,176	25,237	24,060
Repayments of long-term debt	(23,750)	(25,419)	(22,240)
Net Change in Debt, Intercompany	(877)	(240)	(1,428)
Payments for Repurchase of Redeemable Preferred Stock	0	0
Payments for Repurchase of Common Stock	0	0
Payments of Dividends	0	0	0
Dividends paid and returns of contributed capital, Intercompany	(4,644)	(3,092)	(3,846)
Capital contributions from parent	3,908	796	1,179
Net cash (used in) provided by financing activities	4,777	6,533	1,090
Effect of exchange-rate changes on cash and cash equivalents	1	(4)	(1)
Cash and Cash Equivalents, Period Increase (Decrease)	(80)	1,690	931
Cash and Cash Equivalents, at Carrying Value	5,595	3,905	2,974
Cash and Cash Equivalents, at Carrying Value	5,515	5,595	3,905
Affiliated Entity [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Payments for (Proceeds from) Loans and Leases	0	0	0
Affiliated Entity [Member] | Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Payments for (Proceeds from) Loans and Leases	877	240	1,428
Affiliated Entity [Member] | Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Payments for (Proceeds from) Loans and Leases	0	0	0
Affiliated Entity [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Payments for (Proceeds from) Loans and Leases	(67)	1,211	154
Consolidation, Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(1,063)	(2,174)	(4,249)
Payments to Acquire Available-for-sale Securities	0	0	0
Proceeds from sales of available-for-sale securities	0	0	(17)
Proceeds from maturities and repayment of available-for-sale securities	0	0	0
Payments to Acquire Held-to-maturity Securities	0
Payments to Acquire Loans Held-for-investment	0	0	(17)
Proceeds from Sale of Loans Held-for-sale	0	0	0
Originations and repayments of loans held-for-investment and other	0	0	0
Purchases of operating lease assets	0	0	0
Disposals of operating lease assets	0	0	0
Payments to Acquire Interest in Subsidiaries and Affiliates	0
Capital contributions to subsidiaries	3,908	797	1,179
Returns of contributed capital	(3,686)	(1,444)	(1,422)
Proceeds from Divestiture of Businesses		0	0
Increase (Decrease) in Restricted Cash	0	0	0
Increase (Decrease) in Non marketable equity securities	0	0	0
Payments for (Proceeds from) Other Investing Activities	91	0	0
Net cash provided by investing activities	(497)	(2,098)	(1,825)
Proceeds from (Repayments of) Short-term Debt	0	0	0
Increase (Decrease) in Deposits	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Repayments of long-term debt	0	0	0
Net Change in Debt, Intercompany	1,259	1,217	1,376
Payments for Repurchase of Redeemable Preferred Stock	0	0
Payments for Repurchase of Common Stock	0	0
Payments of Dividends	0	0	0
Dividends paid and returns of contributed capital, Intercompany	4,658	3,617	5,672
Capital contributions from parent	(3,908)	(797)	(1,179)
Net cash (used in) provided by financing activities	2,009	4,037	5,869
Effect of exchange-rate changes on cash and cash equivalents	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	449	(235)	(205)
Cash and Cash Equivalents, at Carrying Value	(850)	(615)	(410)
Cash and Cash Equivalents, at Carrying Value	(401)	(850)	(615)
Consolidation, Eliminations [Member] | Affiliated Entity [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Payments for (Proceeds from) Loans and Leases	$ (810)	$ (1,451)	$ (1,582)