Derivative Financial Instruments and Hedging Activities - Derivative Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value	$ 343	$ 418
Designated as Hedging Instrument [Member] \| Liabilities [Member] \| Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	1,000	0
Derivative Asset, Fair Value	0	0
Not Designated as Hedging Instrument [Member] \| Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	11,909	5,369
Derivative Asset, Fair Value	75	16
Not Designated as Hedging Instrument [Member] \| Assets [Member] \| Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	4,122	1,652
Derivative Asset, Fair Value	8	6
Not Designated as Hedging Instrument [Member] \| Assets [Member] \| Interest Rate Cap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	6,327	2,123
Derivative Asset, Fair Value	19	6
Not Designated as Hedging Instrument [Member] \| Assets [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	1,460	1,594
Derivative Asset, Fair Value	48	4
Not Designated as Hedging Instrument [Member] \| Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	13,933	8,475
Derivative Liability, Fair Value	43	46
Not Designated as Hedging Instrument [Member] \| Liabilities [Member] \| Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	8,041	5,627
Derivative Liability, Fair Value	24	39
Not Designated as Hedging Instrument [Member] \| Liabilities [Member] \| Interest Rate Cap [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	5,892	1,804
Derivative Liability, Fair Value	19	6
Not Designated as Hedging Instrument [Member] \| Liabilities [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	0	1,044
Derivative Liability, Fair Value	$ 0	$ 1

Nominal or face amount used to calculate payments on the derivative asset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5579245-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Notional Amount
-URI http://asc.fasb.org/extlink&oid=6519104

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5580258-113959

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- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=51825145&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13495-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Period Type:	instant

- Definition

Nominal or face amount used to calculate payments on the derivative liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5580258-113959

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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