Acquisitions, Divestitures, and Assets Held for Sale - Property Exchange (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Nonmonetary Transaction [Line Items]
Cash paid in property exchange	$ 6,067,000,000	$ 9,508,000,000	$ 7,721,000,000
Wattenberg Properties [Member]
Nonmonetary Transaction [Line Items]
Gain or loss recognized in property exchange			0
Cash paid in property exchange			$ 106,000,000