Subsequent Events (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	0 Months Ended	1 Months Ended	3 Months Ended
	Aug. 06, 2013	Apr. 30, 2014	Mar. 31, 2014	Mar. 31, 2013
Subsequent Event [Line Items]
Stock Repurchase Program, Authorized Amount	$ 200	$ 235
Early extinguishment of debt		26	0	40
Eight And One Over Four Senior Notes [Member] | Senior Notes [Member]
Subsequent Event [Line Items]
Debt Instrument, Repurchased Face Amount			292
Eight And One Over Four Senior Notes [Member] | Subsequent Event [Member] | Senior Notes [Member]
Subsequent Event [Line Items]
Debt Instrument, Repurchased Face Amount		$ 292