Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Land Agreements Not Accounted for under ASC 842 The Company has entered into various long-term land agreements for its wind and solar farms that are not accounted for under ASC 842, primarily in the U.S. and Canada, because the agreements do not convey the right to control the use of the land. In these agreements, the Company does not have exclusive use of the land and the landowners retain the rights to the economic benefits for most of the land. For the three and nine months ended September 30, 2019, the Company recorded rent expenses of $4 million and $12 million, respectively, and $4 million and $13 million for the same periods in 2018, respectively, in project expense in its consolidated statements of operations. Letters of Credit Power Sale Agreements The Company owns and operates wind and solar power projects and has entered into various long-term PSAs that terminate from 2019 to 2043. The terms of these agreements generally provide for the annual delivery of a minimum amount of electricity at fixed prices and in some cases include price escalation over the term of the agreement. Under the terms of these agreements, as of September 30, 2019, irrevocable letters of credits totaling $153 million were available to be issued to guarantee the Company's performance for the duration of the agreements. Project Finance and Other Agreements The Company has various project finance and other agreements which obligate the Company to provide certain reserves to enhance its credit worthiness and facilitate the availability of credit. As of September 30, 2019, irrevocable letters of credit totaling $161 million, which includes letters of credit available under the Revolving Credit Facility, were available to be issued to ensure performance under the various project finance and other agreements. Contingencies Turbine Operating Warranties and Service Guarantees The Company has various turbine availability warranties from its turbine manufacturers and service guarantees from its service and maintenance providers. Pursuant to these guarantees, if a turbine operates at less than minimum availability during the guarantee measurement period, the service provider is obligated to pay, as liquidated damages at the end of the warranty measurement period, an amount for each percent that the turbine operates below the minimum availability threshold. In addition, pursuant to certain of these guarantees, if a turbine operates at more than a specified availability during the guarantee measurement period, the Company has an obligation to pay a bonus to the service provider at the end of the warranty measurement period. As of September 30, 2019, the Company recorded liabilities of $2 million associated with bonuses payable to the turbine manufacturers and service providers. Contingencies in connection with the Broadview Project The Company recorded a $7 million contingent obligation, payable to a third party who holds a 1% interest in Western Interconnect, at fair value upon the acquisition of the Broadview Project. These contingent payments are subject to certain conditions, including the actual energy production of Broadview in a production year and the continued operation of Broadview. Additionally, the Company initially recorded a $29 million contingent obligation, payable to the same counterparty, at fair value using a discount rate of approximately 5% upon acquisition of the Broadview Project. The undiscounted contingent obligation is estimated to be approximately $50 million and is expected to be paid over the life of the PSA term. These contingent payments are subject to certain conditions, including the commercial operation of Grady. The contingent payment is calculated as a percentage of additional transmission revenue earned by Western Interconnect upon Grady's commercial operation, which occurred in August 2019. As of September 30, 2019, the Company has paid approximately $1 million. Contingencies in connection with the Sale of Panhandle 2 interests In connection with the sale of Panhandle 2, the Company agreed to indemnify PSP Investments up to $5 million to cover PSP Investments' pro rata share of the economic impacts resulting from planned transmission outages in the Texas market until December 31, 2019. As of September 30, 2019, the Company has recorded a contingent liability of $4 million associated with the indemnity. Contingencies in connection with Hatchet Ridge On January 29, 2019, Pacific Gas and Electric Company (PG&E) filed voluntary petitions for relief under Chapter 11 of the United States Bankruptcy Code in the United States Bankruptcy Court for the Northern District of California ("the Bankruptcy Court"). The Company has received all post-petition invoiced amounts through September 2019. However, the pre-petition amount of $2 million that relates to production prior to the Chapter 11 filing date remained outstanding as of September 30, 2019 and will be addressed as part of Chapter 11 process. The Company determined that it is probable that substantially all of the consideration to which the entity will be entitled for the electricity delivered to PG&E will be collected; therefore, the Company continues to account for the PSA under ASC 606. The Company evaluated the pre-petition amount of $2 million for impairment in accordance with ASC 450, Contingencies. The Company concluded that it is reasonably possible that Hatchet Ridge's pre-petition amount may be impaired; however, the Company did not recognize any amount for impairment for the nine months ended September 30, 2019. The Company will continue to monitor the bankruptcy proceedings and reassess the pre-petition amount for impairment. Legal Matters From time to time, the Company has become involved in claims and legal matters arising in the ordinary course of business. Management is not currently aware of any matters that will have a material adverse effect on the financial position, results of operations, or cash flows of the Company. Indemnity The Company also enters into indemnity agreements in the ordinary course of business with surety bond providers that issue surety bonds to contractual counterparties in connection with the decommissioning projects and other performance obligations. Pursuant to the indemnity agreements, the Company is obligated, on a joint and several basis with the project company, to indemnify the surety in the event of a draw by the beneficiary. The indemnity obligation is limited to the amount of the bonds and certain related costs and expenses.