Goodwill (details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
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	862
Total other intangible assets, accumulated amortization	492	481
Total other intangible assets, net	370	381
Estimated intangible asset amortization expense, remainder of 2013	34
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