Indebtedness - Summary of Other Non-Recourse Debt (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Other nonrecourse debt, net	$ 4,424	$ 5,286
Participating interest financing \| Minimum
Debt Instrument [Line Items]
Interest rate	0.30%
Participating interest financing \| Maximum
Debt Instrument [Line Items]
Interest rate	5.60%
Trust 2020-1 \| Minimum
Debt Instrument [Line Items]
Interest rate	1.30%
Trust 2020-1 \| Maximum
Debt Instrument [Line Items]
Interest rate	7.50%
Trust 2019-2 \| Minimum
Debt Instrument [Line Items]
Interest rate	2.30%
Trust 2019-2 \| Maximum
Debt Instrument [Line Items]
Interest rate	6.00%
Trust 2019-1 \| Minimum
Debt Instrument [Line Items]
Interest rate	2.70%
Trust 2019-1 \| Maximum
Debt Instrument [Line Items]
Interest rate	6.00%
Trust 2018-3 \| Minimum
Debt Instrument [Line Items]
Interest rate	3.60%
Trust 2018-3 \| Maximum
Debt Instrument [Line Items]
Interest rate	6.00%
Trust 2018-2 \| Minimum
Debt Instrument [Line Items]
Interest rate	3.20%
Trust 2018-2 \| Maximum
Debt Instrument [Line Items]
Interest rate	6.00%
Other nonrecourse debt
Debt Instrument [Line Items]
Other nonrecourse debt, net	$ 4,424	5,286
Unamortized premium, net of debt issuance costs and discount	8	10
Other nonrecourse debt \| Participating interest financing
Debt Instrument [Line Items]
Collateral amount	0
Other nonrecourse debt, net	3,473	4,284
Other nonrecourse debt \| Trust 2020-1
Debt Instrument [Line Items]
Collateral amount	501
Other nonrecourse debt, net	490	0
Other nonrecourse debt \| Trust 2019-2
Debt Instrument [Line Items]
Collateral amount	260
Other nonrecourse debt, net	241	333
Other nonrecourse debt \| Trust 2019-1
Debt Instrument [Line Items]
Collateral amount	236
Other nonrecourse debt, net	212	302
Other nonrecourse debt \| Trust 2018-3
Debt Instrument [Line Items]
Collateral amount	0
Other nonrecourse debt, net	0	209
Other nonrecourse debt \| Trust 2018-2
Debt Instrument [Line Items]
Collateral amount	0
Other nonrecourse debt, net	0	148
Other nonrecourse debt \| Other
Debt Instrument [Line Items]
Other nonrecourse debt, net	$ 4,416	$ 5,276

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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Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
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Amount of unamortized debt discount (premium) and debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

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=119993939&loc=d3e28555-108399

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- Definition

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.

+ References

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