| Cover Page | Oct. 02, 2019 |
| Cover page. | |
| Title of 12(b) Security | Common Stock |
| Document Type | 8-K |
| Document Period End Date | Oct. 2, 2019 |
| Entity File Number | 001-36542 |
| Entity Registrant Name | TerraForm Power, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 46-4780940 |
| Entity Address, Address Line One | 200 Liberty Street, |
| Entity Address, Address Line Two | 14th Floor |
| Entity Address, City or Town | New York, |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10281 |
| City Area Code | 646 |
| Local Phone Number | 992-2400 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001599947 |
| Amendment Flag | false |
| Trading Symbol | TERP |
| Security Exchange Name | NASDAQ |
