Stockholders' Equity - Schedule of Reserve Share of Common Stock for Issuance (Details) - shares	Dec. 31, 2021	Dec. 31, 2020	Jul. 31, 2015
Class of Stock [Line Items]
Shares of common stock reserved for issuance (in shares)	55,467,000	47,311,000
Options outstanding
Class of Stock [Line Items]
Shares of common stock reserved for issuance (in shares)	6,257,000	8,019,000
Restricted stock units outstanding
Class of Stock [Line Items]
Shares of common stock reserved for issuance (in shares)	4,485,000	7,103,000
Sunrun-VSI 2014 Equity Incentive Plan | Employee Stock
Class of Stock [Line Items]
Shares of common stock reserved for issuance (in shares)	11,084,000	8,940,000
2015 Equity Incentive Plan
Class of Stock [Line Items]
Shares of common stock reserved for issuance (in shares)			11,400,000
2015 Equity Incentive Plan | Employee Stock
Class of Stock [Line Items]
Shares of common stock reserved for issuance (in shares)	22,371,000	15,033,000
2015 Employee Stock Purchase Plan | Employee Stock
Class of Stock [Line Items]
Shares of common stock reserved for issuance (in shares)	11,270,000	8,216,000