Legal Matters (Details) - WesternGeco - Settled Litigation			1 Months Ended			3 Months Ended	9 Months Ended	36 Months Ended
	May 16, 2017 USD ($)	Aug. 31, 2012 USD ($)	Apr. 30, 2014 USD ($)	Oct. 31, 2013 USD ($)	Jun. 30, 2009 Patent	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Jul. 02, 2015 USD ($)	Jun. 30, 2015 USD ($)	May 31, 2014 USD ($)
Legal Matters (Textual) [Abstract]
Number of patent apparatus claims contained | Patent					4
Total damages awarded	$ 5,000,000	$ 105,900,000						$ 123,800,000
Amount paid in royalty damages and interest						$ 625,000
Prejudgment interest expense accrued								10,900,000
Forecast
Legal Matters (Textual) [Abstract]
Amount paid in royalty damages and interest							$ 3,750,000
Lost Royalties
Legal Matters (Textual) [Abstract]
Total damages awarded		12,500,000
Lost Profits
Legal Matters (Textual) [Abstract]
Total damages awarded		$ 93,400,000	$ 9,400,000	$ 73,100,000				$ 93,400,000
Reduction in damages awarded in case			$ 3,000,000
Accrual for loss contingency related to legal proceedings									$ 22,000,000	$ 123,800,000