Rate Matters	3 Months Ended
Mar. 31, 2017
Public Utilities, General Disclosures [Abstract]
Rate Matters	Rate Matters Except to the extent noted below, the circumstances set forth in Note 11 to the consolidated financial statements included in PSCo’s Annual Report on Form 10-K for the year ended Dec. 31, 2016, appropriately represent, in all material respects, the current status of other rate matters, and are incorporated herein by reference. Recently Concluded Regulatory Proceeding — Colorado Public Utilities Commission (CPUC) Annual Electric Earnings Test — PSCo must share with customers earnings that exceed the authorized return on equity (ROE) of 9.83 percent for 2015 through 2017, as part of an annual earnings test. The 2016 earnings test did not result in a material customer refund obligation as of Dec. 31, 2016. PSCo filed its 2016 earnings test with the CPUC in April 2017. The final sharing obligation will be based on the CPUC approved tariff and could vary from the current estimate.

Rate Matters

Except to the extent noted below, the circumstances set forth in Note 11 to the consolidated financial statements included in PSCo’s Annual Report on Form 10-K for the year ended Dec. 31, 2016, appropriately represent, in all material respects, the current status of other rate matters, and are incorporated herein by reference.

Recently Concluded Regulatory Proceeding — Colorado Public Utilities Commission (CPUC)

Annual Electric Earnings Test — PSCo must share with customers earnings that exceed the authorized return on equity (ROE) of 9.83 percent for 2015 through 2017, as part of an annual earnings test. The 2016 earnings test did not result in a material customer refund obligation as of Dec. 31, 2016. PSCo filed its 2016 earnings test with the CPUC in April 2017. The final sharing obligation will be based on the CPUC approved tariff and could vary from the current estimate.