Commitments and Contingencies (Details 2) $ in Millions	Dec. 31, 2016 USD ($)
Other Commitments [Line Items]
2016	$ 612
2017	529
2018	448
2019	382
2020	312
2021 and Thereafter	1,947
Total	4,230
Drilling, Equipment, and Purchase Obligations
Other Commitments [Line Items]
2016	255
2017	96
2018	52
2019	27
2020	9
2021 and Thereafter	30
Total	469
Transportation and Gathering Obligations
Other Commitments [Line Items]
2016	250
2017	312
2018	314
2019	275
2020	237
2021 and Thereafter	1,566
Total	2,954
Operating Lease Obligations
Other Commitments [Line Items]
2016	30
2017	42
2018	30
2019	28
2020	28
2021 and Thereafter	188
Total	346
Capital Lease and Other Obligations
Other Commitments [Line Items]
2016	77
2017	79
2018	52
2019	52
2020	38
2021 and Thereafter	163
Total	$ 461