Consolidations and Transfers of Financial Assets Unconsolidated VIEs (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Assets and liabilities recorded in our consolidated balance sheets:
Trading, at fair value	$ 30,768		$ 40,695
Available-for-sale, at fair value	38,171		63,181
Other assets	20,231		27,939
Other liabilities	(15,441)		(14,378)
Unconsolidated VIEs [Member] | Mortgage-Backed Trusts [Member]
Assets and liabilities recorded in our consolidated balance sheets:
Trading, at fair value	14,219		22,706	[1]
Available-for-sale, at fair value	33,307		57,004	[1]
Other assets	119		145	[1]
Other liabilities	(1,668)		(1,449)	[1]
Net carrying amount	45,977		78,406	[1]
Maximum exposure to loss	54,148	[2]	87,397	[1],[2]
Total assets of unconsolidated VIEs	313,202		645,332	[1]
Unconsolidated VIEs [Member] | Limited Partnership Investments [Member]
Assets and liabilities recorded in our consolidated balance sheets:
Maximum exposure to loss	14		118
Total assets of unconsolidated VIEs	6,800		11,700
Fannie Mae Securities [Member]
Assets and liabilities recorded in our consolidated balance sheets:
Trading, at fair value	5,660
Trading, at fair value			6,248
Available-for-sale, at fair value	5,866
Available-for-sale, at fair value			10,435
Non-Fannie Mae Securities [Member]
Assets and liabilities recorded in our consolidated balance sheets:
Trading, at fair value	8,559		16,458	[1]
Available-for-sale, at fair value	$ 27,441		$ 46,569	[1]

[1] Contains securities recognized in our consolidated balance sheets due to consolidation of certain multi-class resecuritization trusts.

[2] Our maximum exposure to loss generally represents the greater of our recorded investment in the entity or the unpaid principal balance of the assets covered by our guaranty. However, our securities issued by Fannie Mae multi-class resecuritization trusts that are not consolidated do not give rise to any additional exposure to loss as we already consolidate the underlying collateral.