Variable Interest Entities - Net Assets (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Noncontrolling interest	$ 310	$ 218
Great Valley Solar
Variable Interest Entity [Line Items]
Non-utility property, less accumulated depreciation	280	284
Other assets	41	39
Total assets	321	323
Term Loan	0	0
Other liabilities	12	13
Total liabilities	12	13
Accumulated depreciation	22	18
Great Valley Solar | Tax Equity Investors
Variable Interest Entity [Line Items]
Noncontrolling interest	90	82
Copper Mountain - Mesquite Solar
Variable Interest Entity [Line Items]
Non-utility property, less accumulated depreciation	439	446
Other assets	176	176
Total assets	615	622
Term Loan	0	0
Other liabilities	76	71
Total liabilities	76	71
Accumulated depreciation	37	30
Copper Mountain - Mesquite Solar | Tax Equity Investors
Variable Interest Entity [Line Items]
Noncontrolling interest	126	$ 134
CED Nevada Virginia
Variable Interest Entity [Line Items]
Non-utility property, less accumulated depreciation	318
Other assets	414
Total assets	732
Term Loan	402
Other liabilities	115
Total liabilities	517
Noncontrolling interest	92
Accumulated depreciation	$ 1