Acquisitions - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended			6 Months Ended	0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2013	Jan. 20, 2015
Business Acquisition [Line Items]
Gain on formation of OneSubsea		$ 1,028,000,000
Acquisitions and investments, net of cash acquired	1,008,000,000	1,210,000,000	845,000,000
One Subsea
Business Acquisition [Line Items]
Purchase price				600,000,000
Ownership interest in joint venture	40.00%
Gain on formation of OneSubsea				1,028,000,000
Other Acquisitions
Business Acquisition [Line Items]
Acquisitions and investments, net of cash acquired	1,008,000,000	610,000,000	845,000,000
Shares of common stock issued in connection with acquisition	2.1
Value of common stock issued in connection with acquisition	213,000,000
Eurasia Drilling Limited | Subsequent Event
Business Acquisition [Line Items]
Ownership interest in joint venture					45.00%
Number of years to purchase remaining shares					2 years
Total cost to acquire minority ownership					$ 1,700,000,000