Subsequent Event (Details) (USD $)	0 Months Ended
	Feb. 05, 2013
Subsequent Event
Subsequent Event, Date	Feb. 05, 2013
Merger consideration
Subsequent Event
Subsequent Event, Amount	13.65
Merger agreement restrictions: dividends
Subsequent Event
Subsequent Event, Amount	0.08
Merger agreement restrictions: commercial paper program
Subsequent Event
Subsequent Event, Amount	1,800,000,000
Merger agreement restrictions: revolving credit facilities
Subsequent Event
Subsequent Event, Amount	2,000,000,000
Merger agreement restrictions: structured financing debt facilities
Subsequent Event
Subsequent Event, Amount	1,500,000,000
Merger agreement restrictions: additional indebtedness
Subsequent Event
Subsequent Event, Amount	25,000,000