Investments	9 Months Ended
Sep. 30, 2018
Investments [Abstract]
Investments	12. INVESTMENTS Investments in Gas Pipeline Trail West Pipeline, LLC (TWP), a wholly-owned subsidiary of TWH, is pursuing the development of a new gas transmission pipeline that would provide an interconnection with NW Natural's utility distribution system. NWN Energy, then a wholly-owned subsidiary of NW Natural, owns 50% of TWH, and 50% is owned by TransCanada American Investments Ltd., an indirect wholly-owned subsidiary of TransCanada Corporation. Variable Interest Entity (VIE) Analysis TWH is a VIE, with NW Natural's investment in TWP reported under equity method accounting. We have determined that NW Natural is not the primary beneficiary of TWH’s activities as it only has a 50% share of the entity, and there are no stipulations that allow a disproportionate influence over it. Investments in TWH and TWP are included in other investments in the balance sheet. If we do not develop this investment, the maximum loss exposure related to TWH is limited to the equity investment balance, less its share of any cash or other assets available as a 50% owner. The investment balance in TWH was $13.4 million at September 30, 2018 and 2017 and December 31, 2017. See Note 12 in the 2017 Form 10-K. Other Investments Other investments include financial investments in life insurance policies, which are accounted for at cash surrender value, net of policy loans. See Note 12 in the 2017 Form 10-K.

12. INVESTMENTS

Investments in Gas Pipeline

Trail West Pipeline, LLC (TWP), a wholly-owned subsidiary of TWH, is pursuing the development of a new gas transmission pipeline that would provide an interconnection with NW Natural's utility distribution system. NWN Energy, then a wholly-owned subsidiary of NW Natural, owns 50% of TWH, and 50% is owned by TransCanada American Investments Ltd., an indirect wholly-owned subsidiary of TransCanada Corporation.

Variable Interest Entity (VIE) Analysis

TWH is a VIE, with NW Natural's investment in TWP reported under equity method accounting. We have determined that NW Natural is not the primary beneficiary of TWH’s activities as it only has a 50% share of the entity, and there are no stipulations that allow a disproportionate influence over it. Investments in TWH and TWP are included in other investments in the balance sheet. If we do not develop this investment, the maximum loss exposure related to TWH is limited to the equity investment balance, less its share of any cash or other assets available as a 50% owner. The investment balance in TWH was $13.4 million at September 30, 2018 and 2017 and December 31, 2017. See Note 12 in the 2017 Form 10-K.

Other Investments

Other investments include financial investments in life insurance policies, which are accounted for at cash surrender value, net of policy loans. See Note 12 in the 2017 Form 10-K.