Asset Charges and Other Costs - Asset Impairment Charges and Loss on Disposal of Non-Core Assets (Details) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2015 USD ($)	Mar. 31, 2015 USD ($) reporting_unit	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Aug. 27, 2015 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of reporting units | reporting_unit		6
Goodwill impairment	$ 517		$ 40	$ 517	$ 40	$ 0
Other long-lived asset impairments				78	4	0
Goodwill				1,764	2,461
Loss on disposal of non-core assets				15	$ 10	$ 0
LeTourneau Offshore Products Unit | Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, including discontinued operation, consideration							$ 100
Loss on disposal of non-core assets				15
CPS
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill impairment		$ 517
Goodwill				$ 52