Indebtedness - Non Recourse Debt (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Non-recourse debt	$ 5,286,000,000	$ 6,795,000,000
Unamortized debt issuance costs, premium and discount	10,000,000	68,000,000
Participating interest financing
Debt Instrument [Line Items]
Collateral Amount	0
Non-recourse debt	4,284,000,000	5,607,000,000
Trust 2019-2
Debt Instrument [Line Items]
Collateral Amount	337,000,000
Non-recourse debt	333,000,000	0
Trust 2019-1
Debt Instrument [Line Items]
Collateral Amount	315,000,000
Non-recourse debt	302,000,000	0
Trust 2018-3
Debt Instrument [Line Items]
Collateral Amount	226,000,000
Non-recourse debt	209,000,000	326,000,000
Trust 2018-2
Debt Instrument [Line Items]
Collateral Amount	168,000,000
Non-recourse debt	148,000,000	250,000,000
Trust 2018-1
Debt Instrument [Line Items]
Collateral Amount	0
Non-recourse debt	0	284,000,000
Trust 2017-2
Debt Instrument [Line Items]
Collateral Amount	0
Non-recourse debt	0	231,000,000
Legacy Asset
Debt Instrument [Line Items]
Collateral Amount	0
Non-recourse debt	0	29,000,000
Other
Debt Instrument [Line Items]
Non-recourse debt	$ 5,276,000,000	$ 6,727,000,000

Amount of assets pledged to secure a debt instrument.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399

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Amount of debt for which creditor does not have general recourse to the debtor but rather has recourse only to the property used for collateral in the transaction or other specific property.

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