Revision of Financial Statements - Condensed Consolidated Statement of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Net income	$ 48	$ 356
Net changes in operating assets and liabilities	(350)	(287)
Net cash provided from continuing operations	183	439
As Previously Reported [Member]
Net income		357
Net changes in operating assets and liabilities		(288)
Net cash provided from continuing operations		439
Revision [Member]
Net income		(1)
Net changes in operating assets and liabilities		$ 1