CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 2,026	$ 1,295
Accounts receivable
Allowance for uncollectible accounts	11	13
Customers	1,553	1,491
Others	512	535
Property, Plant and Equipment, Net [Abstract]
Net properties and equipment related to VIEs	28,936	28,615
Accumulated depreciation, depletion and amortization	38,903	37,905
Other Assets	3,006	2,336
Goodwill and Other Intangible Assets	5,622	5,630
Accounts payable
Trade	1,946	2,003
Other	165	161
Current asset retirement obligations	277	252
Other current liabilities	1,340	1,295
Other Long-term Liabilities
Asset retirement obligations	$ 2,876	$ 2,847
Stockholders’ equity
Common stock, par value per share (in usd per share)	$ 0.1	$ 0.10
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	577,800,000	576,600,000
Treasury stock (in shares)	87,500,000	87,200,000
Variable Interest Entity, Primary Beneficiary [Member]
Current Assets
Cash and cash equivalents	$ 100	$ 92
Accounts receivable
Customers	138	138
Others	11	16
Property, Plant and Equipment, Net [Abstract]
Net properties and equipment related to VIEs	8,630	6,612
Other Assets	1,246	868
Goodwill and Other Intangible Assets	1,279	1,163
Accounts payable
Trade	196	263
Other	6	15
Current asset retirement obligations	23	26
Other current liabilities	107	54
Other Long-term Liabilities
Asset retirement obligations	$ 312	$ 260