Capitalization - Additional Information (Details)	3 Months Ended
Mar. 31, 2021 USD ($)	Feb. 28, 2021 USD ($) project
Borrowings Due 2028 \| Clean Energy Businesses
Schedule of Capitalization [Line Items]
Face amount of debt		$ 250,000,000
Number of solar electric production projects \| project		4
Interest rate		3.39%
Tax Equity Financing Agreement \| Clean Energy Businesses
Schedule of Capitalization [Line Items]
Face amount of debt		$ 270,000,000
Number of solar electric production projects \| project		3
Amount funded from tax equity financing agreement	$ 39,000,000
Senior Notes \| 3.77% Senior Notes Due 2046 \| Clean Energy Businesses
Schedule of Capitalization [Line Items]
Face amount of debt	$ 229,000,000
Interest rate	3.77%
Term Loan \| Term Loan Due June 2021
Schedule of Capitalization [Line Items]
Prepayment of debt	$ 675,000,000

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