Goodwill (details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Goodwill and Other Intangible Assets disclosure
Goodwill, other	$ 27	$ 27
Intangible assets not subject to amortization	216	216
Total other intangible assets, gross carrying amount	862	1,342
Total other intangible assets, accumulated amortization	481	909
Total other intangible assets, net	381	433
Estimated intangible asset amortization expense, 2013	45
Estimated intangible asset amortization expense, 2014	43
Estimated intangible asset amortization expense, 2015	23
Estimated intangible asset amortization expense, 2016	9
Estimated intangible asset amortization expense, 2017	$ 8