Proposed Merger and Basis of Presentation (Details) (USD $) In Millions, except Per Share data, unless otherwise specified		0 Months Ended
	Feb. 02, 2007	Feb. 05, 2013 Merger consideration	Feb. 05, 2013 Merger agreement restrictions: dividends	Feb. 05, 2013 Merger agreement restrictions: commercial paper program	Feb. 05, 2013 Merger agreement restrictions: revolving credit facilities	Feb. 05, 2013 Merger agreement restrictions: structured financing debt facilities	Feb. 05, 2013 Merger agreement restrictions: additional indebtedness
Pending Merger, per share amount		$ 13.65	$ 0.08
Pending Merger, amount				$ 1,800	$ 2,000	$ 1,500	$ 25
Shares issued to subsidiary not considered outstanding	475