Impairment	6 Months Ended
Jun. 30, 2016
Asset Impairment Charges [Abstract]
Impairment	5. Impairment As a result of establishing the Bakken Midstream operating segment in the second quarter of 2015, we performed impairment tests on the Offshore and Onshore reporting units prior to creation of the Bakken Midstream segment in accordance with accounting standards for goodwill. No impairment resulted from this assessment. In addition, we performed separate impairment tests at June 30, 2015, on the allocated goodwill to the Bakken Midstream segment and Onshore reporting unit of the E&P segment following the creation of the Bakken Midstream segment. No impairment existed for the Bakken Midstream segment, but goodwill allocated to the Onshore reporting unit of $385 million did not pass the impairment test. As a result, we recorded a noncash charge of $385 million in the second quarter of 2015 to reduce the Onshore reporting unit goodwill to its implied fair value of zero based on a hypothetical purchase price allocation as stipulated in the accounting standards.

Impairment

6 Months Ended

Jun. 30, 2016

5. Impairment

As a result of establishing the Bakken Midstream operating segment in the second quarter of 2015, we performed impairment tests on the Offshore and Onshore reporting units prior to creation of the Bakken Midstream segment in accordance with accounting standards for goodwill. No impairment resulted from this assessment. In addition, we performed separate impairment tests at June 30, 2015, on the allocated goodwill to the Bakken Midstream segment and Onshore reporting unit of the E&P segment following the creation of the Bakken Midstream segment. No impairment existed for the Bakken Midstream segment, but goodwill allocated to the Onshore reporting unit of $385 million did not pass the impairment test. As a result, we recorded a noncash charge of $385 million in the second quarter of 2015 to reduce the Onshore reporting unit goodwill to its implied fair value of zero based on a hypothetical purchase price allocation as stipulated in the accounting standards.