Divestiture and Discontinued Operations [Details 6] (USD $) In Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010		Mar. 31, 2011	Dec. 31, 2010		Sep. 30, 2010	Mar. 31, 2010	Dec. 31, 2009
Combined results of the discontinued operations
Net interest income	$ 564		$ 617		$ 1,161		$ 1,242
Net interest income (expense) after provision for loan and lease losses	572		389		1,209		601
Noninterest income	454		492		911		942
Noninterest expense	680		769		1,381		1,554
Income (loss) before income taxes	(15)		(44)		(32)		(40)
Income taxes	94		11		205		(71)
Income (loss) from discontinued operations, net of taxes	(9)		(27)		(20)		(25)
Combined assets and liabilities of the discontinued operations
Cash and due from banks	853		591		853		591			278				471
Loans, net of unearned income of $1, $1 and $1	47,840		53,334		47,840		53,334			50,107
Less: Allowance for loan and lease losses	1,230		2,219		1,230		2,219			1,604
Net loans	46,610		51,115		46,610		51,115			48,503
Loans held for sale	381		699		381		699		426	467		637	556
Other intangible assets	19		42		19		42			21
Accrued income and other assets	2,968	[1]	4,061	[1]	2,968	[1]	4,061	[1]		3,876	[1]
Total assets	6,328	[1]	6,814	[1]	6,328	[1]	6,814	[1]		6,554	[1]
Accrued expense and other liabilities	1,518		2,154		1,518		2,154			1,931
Total liabilities	2,950	[1]	3,139	[1]	2,950	[1]	3,139	[1]		2,998	[1]
Segment, Discontinued Operations [Member]
Combined results of the discontinued operations
Net interest income	35		39		71		79
Provision for loan and lease losses	30		14		62		38
Net interest income (expense) after provision for loan and lease losses	5		25		9		41
Noninterest income	(11)		(54)		(20)		(52)
Noninterest expense	9		15		21		29
Income taxes	(6)		(17)		(12)		(15)
Combined assets and liabilities of the discontinued operations
Cash and due from banks	32		32		32		32			33
Loans at fair value	3,100		3,223		3,100		3,223			3,125
Loans, net of unearned income of $1, $1 and $1	3,161		3,371		3,161		3,371			3,326
Less: Allowance for loan and lease losses	109		128		109		128			114
Net loans	6,152		6,466		6,152		6,466			6,337
Loans held for sale	0		92		0		92			15
Other intangible assets	0		1		0		1			0
Accrued income and other assets	144		223		144		223			169
Accrued expense and other liabilities	31		47		31		47			32
Securities at fair value	$ 2,919		$ 3,092		$ 2,919		$ 3,092			$ 2,966

[1] The assets of the VIEs can only be used by the particular VIE and there is no recourse to Key with respect to the liabilities of the consolidated education loan securitization trust VIEs for LIHTC.