Variable Interest Entities - Schedule of Sale and Deconsolidation of Transaction (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended		1 Months Ended
	Jun. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	May 31, 2014 CCH [Member]
Variable Interest Entity [Line Items]
Proceeds from sale, net of transaction costs of $1		$ 108		$ 108
Non-utility property, less accumulated depreciation	(197)	(197)	(605)	(341)
Other assets, including working capital				(31)
Long-term debt, including current portion	11,129	11,129	10,974	217
Other liabilities				9
Gain on sale of solar energy projects	(45)	(45)		(45)
Equity method investment upon deconsolidation				$ (83)