Financial Risk Management Activities - Corporate Financial Risk Management Activities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) MMBbls
Derivative Instruments Gain Loss [Line Items]
After-tax deferred gains in Accumulated other comprehensive income (loss)	$ (1,667,000,000)		$ (1,704,000,000)
Interest Rate Swaps
Derivative Instruments Gain Loss [Line Items]
Outstanding gross notional amount	350,000,000		350,000,000
Unrealized change in fair value of interest rate swaps - increase/(decrease)	(1,000,000)	$ 14,000,000
Foreign Exchange
Derivative Instruments Gain Loss [Line Items]
Outstanding gross notional amount	69,000,000		785,000,000
Total foreign exchange gains and (losses) reported in Other, net in Revenues and Non-Operating Income in the Statement of Consolidated Income	(1,000,000)	6,000,000
Loss on foreign exchange contracts not designated as hedging instruments	(1,000,000)	(20,000,000)
After tax foreign currency translation adjustments included in Accumulated other comprehensive income (loss)	14,000,000	$ 169,000,000
Accumulated cumulative currency translation adjustment	(1,031,000,000)		$ (1,045,000,000)
Crude Oil Collars
Derivative Instruments Gain Loss [Line Items]
Increased (decreased) E&P sales and other operating revenue	1,000,000
Increased (decreased) E&P sales and other operating revenue after income tax	1,000,000
After-tax deferred gains in Accumulated other comprehensive income (loss)	$ 2,000,000
Outstanding gross notional amount, in millions of barrels | MMBbls			0