Discontinued Operations - Summarized Results of Operations for Discontinued Operations (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Revenue	$ 10	$ 43	$ 15	$ 103
Operating income		11		35
Interest expense	0	(3)	0	(8)
Income from operations before income taxes		8		27
Provision for income taxes		(4)		(11)
Income from operations		4		16
Gain on sale, net of tax		303		303
Income from discontinued operations		$ 307		$ 319