Long-Lived Asset Impairments Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges		$ 436
Long-Lived Asset Impairments and Other Charges	$ 928	436	$ 638
Tangible Asset Impairment Charges	923	388
Impairment of Intangible Assets (Excluding Goodwill)	5	48
Drilling Rights [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	740
Western Hemisphere [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	135
Eastern Hemisphere [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	37
Corporate, Non-Segment [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	$ 11
North America [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible Asset Impairment Charges		251
Impairment of Intangible Assets (Excluding Goodwill)		35
Drilling Rigs [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Long-Lived Asset Impairments and Other Charges			255
Middle East/North Africa/Asia [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible Asset Impairment Charges		137
Europe/Sub-Sahara Africa/Russia [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)		$ 13
Drilling Tools, Pressure Pumping and Wireline [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Long-Lived Asset Impairments and Other Charges			259
Pressure Pumping [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Long-Lived Asset Impairments and Other Charges			$ 124