Commitments and Contingencies - Contractual Obligations (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Oil and Gas Delivery Commitments and Contracts [Line Items]
Decrease in commitments	$ 3,490
Reduction of other operating lease commitments	291
Drilling Rig Commitments [Member]
Oil and Gas Delivery Commitments and Contracts [Line Items]
Decrease in commitments	999
Drilling Rig Commitments [Member] | Kitimat LNG [Member]
Oil and Gas Delivery Commitments and Contracts [Line Items]
Decrease in commitments	79
Purchase Obligations [Member]
Oil and Gas Delivery Commitments and Contracts [Line Items]
Decrease in commitments	1,248
Purchase Obligations [Member] | Kitimat LNG [Member]
Oil and Gas Delivery Commitments and Contracts [Line Items]
Decrease in commitments	651
Firm Transportation Agreements [Member]
Oil and Gas Delivery Commitments and Contracts [Line Items]
Decrease in commitments	431
Firm Transportation Agreements [Member] | Kitimat LNG [Member]
Oil and Gas Delivery Commitments and Contracts [Line Items]
Decrease in commitments	$ 51