Fair Value Level 3 Valuation - Nonrecurring (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 7,303	$ 7,825
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	110	229
Mortgage loans held for investment, at fair value	3,400,773	3,270,535
Total assets at fair value	3,461,999	3,313,691
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	7,892	7,054
Mortgage loans held for investment, at fair value	195,726	127,650
Total assets at fair value	205,309	136,048
Fair Value, Nonrecurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	15	274
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	2,031	1,076
Total assets at fair value	3,511	2,598
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Single Vendor Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	720	605
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Consensus Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	$ 1,311	$ 471
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Accepted Offers [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Number of Acquired Properties Valuated, Percentage	21.00%	12.00%
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Proprietary Home Price Model and Appraisals [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Number of Acquired Properties Valuated, Percentage	75.00%	85.00%
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Single-family [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	$ 622	$ 918
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Single-family [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	35	51
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Single-family [Member] \| Internal Model [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	759	555
Acquired property, net	92	164
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Single-family [Member] \| Accepted Offers [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	105	101
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Single-family [Member] \| Appraisals [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	204	362
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Single-family [Member] \| Walk Forwards [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	186	240
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Multifamily [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	75	40
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Multifamily [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	75	16
Acquired property, net	24	9
Fair Value, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Multifamily [Member] \| Asset Manager Estimate [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 0	$ 24

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- Definition

Carrying amount as of the balance sheet date of real estate owned and foreclosed assets. Foreclosed assets include all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings.

+ References

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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Fair value portion of mortgage loans held-for-sale.

+ References

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