Divestitures (Notes)	6 Months Ended
Jun. 30, 2019
Business Combinations [Abstract]
Mergers, Acquisitions and Dispositions Disclosures [Text Block]	Sale of Garrison Energy Center and RockGen Energy Center On July 10, 2019, we, through our indirect, wholly owned subsidiaries Calpine Holdings, LLC and Calpine Northbrook Project Holdings, LLC, completed the sale of 100% of our ownership interests in Garrison Energy Center LLC (“Garrison”) and RockGen Energy LLC (“RockGen”) to Cobalt Power, L.L.C. for approximately $360 million, subject to certain working capital adjustments and the execution of financial commodity contracts. Garrison owns the Garrison Energy Center, a 309 MW natural gas-fired, combined-cycle power plant located in Dover, Delaware, and RockGen owns the RockGen Energy Center, a 503 MW natural gas-fired, simple-cycle power plant located in Christiana, Wisconsin. We used the sale proceeds, together with cash on hand, to fund a dividend of $400 million to our parent, CPN Management, LP. At June 30, 2019, the assets and liabilities of Garrison and RockGen, which are part of our East segment, were classified as current assets and liabilities held for sale on our Consolidated Condensed Balance Sheet consisting primarily of property, plant and equipment, net, and finance leases, respectively. We recorded impairment losses of $40 million and $55 million during the three and six months ended June 30, 2019, respectively, associated with the sale to adjust the carrying value of the assets to reflect fair value less cost to sell.

Divestitures (Notes)

6 Months Ended

Jun. 30, 2019

Mergers, Acquisitions and Dispositions Disclosures [Text Block]

Sale of Garrison Energy Center and RockGen Energy Center

On July 10, 2019, we, through our indirect, wholly owned subsidiaries Calpine Holdings, LLC and Calpine Northbrook Project Holdings, LLC, completed the sale of 100% of our ownership interests in Garrison Energy Center LLC (“Garrison”) and RockGen Energy LLC (“RockGen”) to Cobalt Power, L.L.C. for approximately $360 million, subject to certain working capital adjustments and the execution of financial commodity contracts. Garrison owns the Garrison Energy Center, a 309 MW natural gas-fired, combined-cycle power plant located in Dover, Delaware, and RockGen owns the RockGen Energy Center, a 503 MW natural gas-fired, simple-cycle power plant located in Christiana, Wisconsin. We used the sale proceeds, together with cash on hand, to fund a dividend of $400 million to our parent, CPN Management, LP.

At June 30, 2019, the assets and liabilities of Garrison and RockGen, which are part of our East segment, were classified as current assets and liabilities held for sale on our Consolidated Condensed Balance Sheet consisting primarily of property, plant and equipment, net, and finance leases, respectively. We recorded impairment losses of $40 million and $55 million during the three and six months ended June 30, 2019, respectively, associated with the sale to adjust the carrying value of the assets to reflect fair value less cost to sell.