Fair Value Recurring Changes in Fair Value (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Trading securities	$ 18,477		$ 17,950
Available-for-sale securities	0		0
Mortgage loans held for investment, at amortized cost	0		0
Other assets [Abstract]
Derivatives assets at fair value	0		0
Total assets at fair value	86,125		93,736
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Total liabilities at fair value	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Cash equivalents	6,725	[1]	1,150	[1]
Trading securities	18,477		17,950
Available-for-sale securities	0		0
Other assets [Abstract]
Derivatives assets at fair value	0		0
Total assets at fair value	25,202		19,100
Liabilities [Abstract]
Long-term debt, fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Total liabilities at fair value	0		0
Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Trading securities	2,959		2,286
Available-for-sale securities	24,340		25,034
Mortgage loans held for investment, at amortized cost	406,415		466,594
Other assets [Abstract]
Derivatives assets at fair value	105		175
Total assets at fair value	435,326		495,561
Other liabilities [Abstract]
Derivative liabilities at fair value	154		161
Total liabilities at fair value	20,829		23,984
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Cash equivalents	0	[1]	0	[1]
Trading securities	2,959		2,286
Available-for-sale securities	24,340		25,034
Other assets [Abstract]
Derivatives assets at fair value	105		175
Total assets at fair value	30,365		30,129
Liabilities [Abstract]
Long-term debt, fair value	1,414		1,528
Other liabilities [Abstract]
Derivative liabilities at fair value	154		161
Total liabilities at fair value	1,568		1,689
Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Trading securities	18,753		20,459
Available-for-sale securities	31,196		38,147
Mortgage loans held for investment, at amortized cost	2,584,593		2,567,022
Other assets [Abstract]
Derivatives assets at fair value	15,417		16,051
Total assets at fair value	2,704,343		2,694,632
Other liabilities [Abstract]
Derivative liabilities at fair value	18,535		22,590
Total liabilities at fair value	3,280,283		3,347,367
Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Cash equivalents	0	[1]	0	[1]
Trading securities	18,753		20,459
Available-for-sale securities	31,196		38,147
Other assets [Abstract]
Derivatives assets at fair value	15,417		16,051
Total assets at fair value	76,175		82,823
Liabilities [Abstract]
Long-term debt, fair value	13,907		10,912
Other liabilities [Abstract]
Derivative liabilities at fair value	18,535		22,590
Total liabilities at fair value	32,442		33,502
Netting Adjustment [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Mortgage loans held for investment, at amortized cost	0		0
Other assets [Abstract]
Derivatives assets at fair value	(12,073)		(15,791)
Total assets at fair value	(12,073)		(15,791)
Other liabilities [Abstract]
Derivative liabilities at fair value	(15,785)		(22,046)
Total liabilities at fair value	(15,785)		(22,046)
Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Cash equivalents	0	[1]	0	[1]
Trading securities	0		0
Available-for-sale securities	0		0
Other assets [Abstract]
Derivatives assets at fair value	(12,073)	[2]	(15,791)	[2]
Total assets at fair value	(12,073)	[2]	(15,791)	[2]
Liabilities [Abstract]
Long-term debt, fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	(15,785)	[2]	(22,046)	[2]
Total liabilities at fair value	(15,785)	[2]	(22,046)	[2]
Estimated Fair Value [Member]
Assets [Abstract]
Trading securities	40,189		40,695
Available-for-sale securities	55,536		63,181
Mortgage loans held for investment, at amortized cost	2,991,008		3,033,616
Other assets [Abstract]
Derivatives assets at fair value	3,449		435
Total assets at fair value	3,213,721		3,268,138
Other liabilities [Abstract]
Derivative liabilities at fair value	2,904		705
Total liabilities at fair value	3,285,327		3,349,305
Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Cash equivalents	6,725	[1]	1,150	[1]
Trading securities	40,189		40,695
Available-for-sale securities	55,536		63,181
Other assets [Abstract]
Derivatives assets at fair value	3,449		435
Total assets at fair value	119,669		116,261
Liabilities [Abstract]
Long-term debt, fair value	15,321		12,440
Other liabilities [Abstract]
Derivative liabilities at fair value	2,904		705
Total liabilities at fair value	18,225		13,145
Fannie Mae [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Fannie Mae [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	52		68
Available-for-sale securities	10		29
Fannie Mae [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	6,146		6,180
Available-for-sale securities	8,085		10,406
Fannie Mae [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Fannie Mae [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	6,198		6,248
Available-for-sale securities	8,095		10,435
Freddie Mac [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Freddie Mac [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	2		2
Available-for-sale securities	9		10
Freddie Mac [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	2,845		2,791
Available-for-sale securities	7,869		9,370
Freddie Mac [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Freddie Mac [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	2,847		2,793
Available-for-sale securities	7,878		9,380
Ginnie Mae [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Ginnie Mae [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	2		1
Available-for-sale securities	0		0
Ginnie Mae [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	351		436
Available-for-sale securities	668		751
Ginnie Mae [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Ginnie Mae [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	353		437
Available-for-sale securities	668		751
Alt-A private-label securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Alt-A private-label securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	703		104
Available-for-sale securities	7,008		6,564
Alt-A private-label securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	778		1,226
Available-for-sale securities	4,119		4,511
Alt-A private-label securities [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Alt-A private-label securities [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	1,481		1,330
Available-for-sale securities	11,127		11,075
Subprime private-label securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Subprime private-label securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	1,488		1,319
Available-for-sale securities	7,862		7,447
Subprime private-label securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Subprime private-label securities [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Subprime private-label securities [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	1,488		1,319
Available-for-sale securities	7,862		7,447
CMBS [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
CMBS [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
CMBS [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	8,633		9,826
Available-for-sale securities	10,445		13,097
CMBS [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
CMBS [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	8,633		9,826
Available-for-sale securities	10,445		13,097
Mortgage revenue bonds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Mortgage revenue bonds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	603		675
Available-for-sale securities	6,400		7,837
Mortgage revenue bonds [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	4		5
Mortgage revenue bonds [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Mortgage revenue bonds [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	603		675
Available-for-sale securities	6,404		7,842
Other [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Other [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	109		117
Available-for-sale securities	3,051		3,147
Other [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	6		7
Other [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
Available-for-sale securities	0		0
Other [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	109		117
Available-for-sale securities	3,057		3,154
U.S. Treasury Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	18,477		17,950
U.S. Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
U.S. Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
U.S. Treasury Securities [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	0		0
U.S. Treasury Securities [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	18,477		17,950
Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	720		793
Fannie Mae [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	0		0
Liabilities [Abstract]
Long-term debt, fair value	0		0
Fannie Mae [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	0		0
Fannie Mae [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	225,059		232,170
Liabilities [Abstract]
Long-term debt, fair value	944		1,056
Fannie Mae [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	337		400
Fannie Mae [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	38,280		39,018
Liabilities [Abstract]
Long-term debt, fair value	512,058		534,516
Fannie Mae [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	383		393
Fannie Mae [Member] | Netting Adjustment [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	0		0
Liabilities [Abstract]
Long-term debt, fair value	0		0
Fannie Mae [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	0		0
Fannie Mae [Member] | Estimated Fair Value [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	263,339		271,188
Liabilities [Abstract]
Long-term debt, fair value	513,002		535,572
Fannie Mae [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	720		793
Consolidated Trusts [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	13,770		10,800
Liabilities [Abstract]
Long-term debt, fair value	14,601		11,647
Consolidated Trusts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	0		0
Liabilities [Abstract]
Long-term debt, fair value	0		0
Consolidated Trusts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	0		0
Liabilities [Abstract]
Long-term debt, fair value	0		0
Consolidated Trusts [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	181,356		234,424
Liabilities [Abstract]
Long-term debt, fair value	14,554		16,171
Consolidated Trusts [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	2,961		2,634
Liabilities [Abstract]
Long-term debt, fair value	1,077		1,128
Consolidated Trusts [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	2,546,313		2,528,004
Liabilities [Abstract]
Long-term debt, fair value	2,646,877		2,685,008
Consolidated Trusts [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	10,809		8,166
Liabilities [Abstract]
Long-term debt, fair value	13,524		10,519
Consolidated Trusts [Member] | Netting Adjustment [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	0		0
Liabilities [Abstract]
Long-term debt, fair value	0		0
Consolidated Trusts [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	0		0
Liabilities [Abstract]
Long-term debt, fair value	0		0
Consolidated Trusts [Member] | Estimated Fair Value [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	2,727,669		2,762,428
Liabilities [Abstract]
Long-term debt, fair value	2,661,431		2,701,179
Consolidated Trusts [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Assets [Abstract]
Mortgage loans held for investment, at amortized cost	13,770		10,800
Liabilities [Abstract]
Long-term debt, fair value	14,601		11,647
Swaps [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Swaps [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	78		146
Other liabilities [Abstract]
Derivative liabilities at fair value	121		154
Swaps [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	11,441		12,224
Other liabilities [Abstract]
Derivative liabilities at fair value	14,882		19,836
Swaps [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Swaps [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	11,519		12,370
Other liabilities [Abstract]
Derivative liabilities at fair value	15,003		19,990
Swaptions [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Swaptions [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Swaptions [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	1,786		3,674
Other liabilities [Abstract]
Derivative liabilities at fair value	2,015		2,463
Swaptions [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Swaptions [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	1,786		3,674
Other liabilities [Abstract]
Derivative liabilities at fair value	2,015		2,463
Other [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value			0
Other [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	27		26
Other liabilities [Abstract]
Derivative liabilities at fair value			0
Other [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value			1
Other [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value			0
Other [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	27		26
Other liabilities [Abstract]
Derivative liabilities at fair value			1
Mortgage commitment derivatives [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Mortgage commitment derivatives [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		3
Other liabilities [Abstract]
Derivative liabilities at fair value	33		7
Mortgage commitment derivatives [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	2,190		153
Other liabilities [Abstract]
Derivative liabilities at fair value	1,638		290
Mortgage commitment derivatives [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Mortgage commitment derivatives [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	2,190		156
Other liabilities [Abstract]
Derivative liabilities at fair value	1,671		297
Netting adjustment [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Netting adjustment [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Netting adjustment [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	0		0
Other liabilities [Abstract]
Derivative liabilities at fair value	0		0
Netting adjustment [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	(12,073)	[2]	(15,791)	[2]
Other liabilities [Abstract]
Derivative liabilities at fair value	(15,785)	[2]	(22,046)	[2]
Netting adjustment [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivatives assets at fair value	(12,073)		(15,791)
Other liabilities [Abstract]
Derivative liabilities at fair value	(15,785)		(22,046)
Senior Fixed [Member] | Fannie Mae [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	0		0
Senior Fixed [Member] | Fannie Mae [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	0		0
Senior Fixed [Member] | Fannie Mae [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	383		393
Senior Fixed [Member] | Fannie Mae [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	0		0
Senior Fixed [Member] | Fannie Mae [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	383		393
Senior Floating [Member] | Fannie Mae [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	0		0
Senior Floating [Member] | Fannie Mae [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	337		400
Senior Floating [Member] | Fannie Mae [Member] | Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	0		0
Senior Floating [Member] | Fannie Mae [Member] | Netting Adjustment [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	0		0
Senior Floating [Member] | Fannie Mae [Member] | Estimated Fair Value [Member] | Recurring Fair Value Measurements [Member]
Liabilities [Abstract]
Long-term debt, fair value	$ 337		$ 400

[1] Cash equivalents are comprised of U.S. Treasuries that are classified as Level 1.

[2] Derivative contracts are reported on a gross basis by level. The netting adjustment represents the effect of the legal right to offset under legally enforceable master netting agreements to settle with the same counterparty on a net basis, including cash collateral posted and received.