Commitments, Guarantees and Contingent Liabilities (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments, Guarantees and Contingent Liabilities
Total rent expense for all leases	$ 243	$ 256	$ 256
Capital leases, future minimum lease payments
2013	19
2014	17
2015	7
2016	7
2017	2
Thereafter	11
Total	63
Present value of minimum capital lease payments	55
Operating leases, future minimum lease payments
2013	166
2014	130
2015	99
2016	72
2017	43
Thereafter	70
Total	$ 580

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Amount of minimum lease payments for capital leases.

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