Indebtedness - Summary of Other Non-Recourse Debt (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Non-recourse debt	$ 5,533,000,000	$ 6,795,000,000
Unamortized debt issuance costs, premium and discount	12,000,000	68,000,000
Participating interest financing
Debt Instrument [Line Items]
Non-recourse debt	4,581,000,000	5,607,000,000
Trust 2017-2
Debt Instrument [Line Items]
Non-recourse debt	0	231,000,000
Trust 2018-1
Debt Instrument [Line Items]
Non-recourse debt	201,000,000	284,000,000
Trust 2018-2
Debt Instrument [Line Items]
Non-recourse debt	161,000,000	250,000,000
Trust 2018-3
Debt Instrument [Line Items]
Non-recourse debt	239,000,000	326,000,000
Trust 2019-1
Debt Instrument [Line Items]
Non-recourse debt	339,000,000	0
Nonrecourse debt - legacy assets
Debt Instrument [Line Items]
Non-recourse debt	0	29,000,000
Other
Debt Instrument [Line Items]
Non-recourse debt	5,521,000,000	$ 6,727,000,000
Nonrecourse debt–legacy assets \| Participating interest financing
Debt Instrument [Line Items]
Securitized Amount	0
Nonrecourse debt–legacy assets \| Trust 2017-2
Debt Instrument [Line Items]
Securitized Amount	0
Nonrecourse debt–legacy assets \| Trust 2018-1
Debt Instrument [Line Items]
Securitized Amount	232,000,000
Nonrecourse debt–legacy assets \| Trust 2018-2
Debt Instrument [Line Items]
Securitized Amount	179,000,000
Nonrecourse debt–legacy assets \| Trust 2018-3
Debt Instrument [Line Items]
Securitized Amount	254,000,000
Nonrecourse debt–legacy assets \| Trust 2019-1
Debt Instrument [Line Items]
Securitized Amount	347,000,000
Nonrecourse debt–legacy assets \| Nonrecourse debt - legacy assets
Debt Instrument [Line Items]
Securitized Amount	$ 0

Face (par) amount of debt instrument at time of issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
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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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