Lease Commitments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Leases [Abstract]
Operating leases, minimum annual rentals in 2013	$ 53
Operating leases, minimum annual rentals in 2014	38
Operating leases, minimum annual rentals in 2015	28
Operating leases, minimum annual rentals in 2016	20
Operating leases, minimum annual rentals in 2017	16
Operating leases, minimum annual rentals, thereafter	62
Minimum sublease rentals	5
Rental expense (net of sublease rental income)	$ 63	$ 62	$ 60