Dispositions Dispositions (Details) - USD ($) $ in Millions					3 Months Ended
	Apr. 21, 2017	Apr. 07, 2017	Jan. 27, 2016	Jan. 01, 2016	Mar. 31, 2017	Mar. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of Long-Lived Assets Held-for-use					$ 168	$ 159
Proceeds from the sale of businesses, net of cash sold, and equity method investments					4	115
Gain (Loss) on Disposition of Business					0	(47)
Proceeds from sale of ownership interest					0	(134)
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Kazakhstan [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pre-tax loss of disposed businesses, Excluding gain on disposal, included in continuing operations					81
Pre-tax income of disposed businesses, Excluding gain on disposal, included in continuing operations						8
Kazakhstan [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of Long-Lived Assets Held-for-use					94	$ 0
DPLER [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from the sale of businesses, net of cash sold, and equity method investments				$ 76
Gain (Loss) on Disposition of Business				$ (49)
Kelanitissa [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from the sale of businesses, net of cash sold, and equity method investments			$ 18
Gain (Loss) on Disposition of Business			$ 5
Long Lived Assets Held And Used [Member] | Kazakhstan [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets Carrying Amount Disclosure Nonrecurring					92
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Kazakhstan [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of Long-Lived Assets to be Disposed of					94
Assets Carrying Amount Disclosure Nonrecurring					171
Fair Value Less Costs To Sell					$ 29
Subsequent Event [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from the sale of businesses, net of cash sold, and equity method investments	$ 50
Subsequent Event [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Kazakhstan [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from the sale of businesses, net of cash sold, and equity method investments		$ 24
Gain (Loss) on Disposition of Business		$ 48