Commitments, Contingent Liabilities and Guarantees (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2011 Y	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Contingent Liabilities and Guarantees (Textual) [Abstract]
Rental expense under all operating leases	$ 120,000,000	$ 124,000,000	$ 119,000,000
Minimum future rental payments under noncancelable operating leases due in 2012	115,000,000
Minimum future rental payments under noncancelable operating leases due in 2013	114,000,000
Minimum future rental payments under noncancelable operating leases due in 2014	110,000,000
Minimum future rental payments under noncancelable operating leases due in 2015	103,000,000
Minimum future rental payments under noncancelable operating leases due in 2016	86,000,000
Minimum future rental payments under noncancelable operating leases, all subsequent years	306,000,000
Investment losses of Austin, an investment subsidiary, max limit				186,000,000
Self-insurance deductible				25,000,000
Standby letters of credit
Remaining Weighted Average Life of Standby Letters of Credit	2.9
Remaining actual life	From less than one year to as many as seven years
Recourse agreement with FNMA
Weighted average remaining term for outstanding commercial mortgage loans	6
Unpaid principal balance outstanding of loans sold	2,800,000,000
Potential undiscounted future payments, maximum limit	One-third of principal balance of loan outstanding
Written put options
Weighted average life of written put options	1.8
Default guarantees
Terms of default guarantees range	From less than 1 year to as many as 7 years
Other Off-Balance Sheet Risk
Obligation for credit market disruption	51,000,000
Expiration date of liquidity facility	May 31, 2013
Aggregate amount available to be drawn of current commitments	$ 25,000,000