Long-term Debt - Debt Table (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt	$ 6,792	$ 6,858
Current portion of long-term debt	(361)	(1,824)
Debt issuance costs, net	(79)	(78)
Add premiums	5	0
Long-term debt, excluding current maturities	6,357	4,956
2020 Convertible Notes
Debt Instrument [Line Items]
Long-term debt	$ 0	45
Debt instrument, interest rate, stated percentage	3.25%
2024 Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 0	88
Debt instrument, interest rate, stated percentage	5.375%
2025 Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 600	600
Debt instrument, interest rate, stated percentage	5.75%
2026 Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 350	350
Debt instrument, interest rate, stated percentage	5.00%
2028 Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 850	600
Debt instrument, interest rate, stated percentage	4.75%
Clearway Energy LLC and Clearway Energy Operating LLC Revolving Credit Facility, due 2023 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.00%
Clearway Energy LLC and Clearway Energy Operating LLC Revolving Credit Facility, due 2023 | Letter of Credit
Debt Instrument [Line Items]
Long-term debt	$ 0	0
Letters of credit outstanding, amount	59
Subtotal project-level debt:
Debt Instrument [Line Items]
Long-term debt	4,992	5,175
Alpine, due 2022
Debt Instrument [Line Items]
Long-term debt	$ 0	119
Alpine, due 2022 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.00%
Alpine, due 2022 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 0
Alta Wind I-V lease financing arrangements, due 2034 and 2035
Debt Instrument [Line Items]
Long-term debt	$ 816	844
Alta Wind I-V lease financing arrangements, due 2034 and 2035 | Minimum
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	5.696%
Alta Wind I-V lease financing arrangements, due 2034 and 2035 | Maximum
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	7.015%
Alta Wind I-V lease financing arrangements, due 2034 and 2035 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 29
Buckthorn Solar, due 2025
Debt Instrument [Line Items]
Long-term debt	$ 127	129
Buckthorn Solar, due 2025 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%
Buckthorn Solar, due 2025 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 26
Carlsbad Holdco, due 2038
Debt Instrument [Line Items]
Long-term debt	$ 215	216
Debt instrument, interest rate, stated percentage	4.21%
Carlsbad Holdco, due 2038 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 9
Carlsbad Energy Holdings LLC, due 2027 and 2038
Debt Instrument [Line Items]
Long-term debt	568	582
Carlsbad Energy Holdings LLC, due 2027 and 2038 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	67
Chestnut Borrower, LLC, due 2024
Debt Instrument [Line Items]
Long-term debt	$ 109	0
Chestnut Borrower, LLC, due 2024 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.50%
Chestnut Borrower, LLC, due 2024 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 8
CS4 Borrower, due 2026
Debt Instrument [Line Items]
Long-term debt	$ 103	0
CS4 Borrower, due 2026 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.00%
CS4 Borrower, due 2026 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 4
CVSR, due 2037
Debt Instrument [Line Items]
Long-term debt	$ 675	696
CVSR, due 2037 | Minimum
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	2.339%
CVSR, due 2037 | Maximum
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.775%
CVSR, due 2037 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 0
CVSR Holdco Notes, due 2037
Debt Instrument [Line Items]
Long-term debt	$ 176	182
Debt instrument, interest rate, stated percentage	4.68%
CVSR Holdco Notes, due 2037 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 13
Duquesne, due 2059
Debt Instrument [Line Items]
Long-term debt	$ 95	95
Debt instrument, interest rate, stated percentage	4.62%
Duquesne, due 2059 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 0
El Segundo Energy Center, due 2023
Debt Instrument [Line Items]
Long-term debt	$ 250	303
El Segundo Energy Center, due 2023 | Minimum | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.875%
El Segundo Energy Center, due 2023 | Maximum | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.50%
El Segundo Energy Center, due 2023 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 138
Energy Center Minneapolis Series D, E, F, G, H Notes, due 2025-2037
Debt Instrument [Line Items]
Long-term debt	327	328
Energy Center Minneapolis Series D, E, F, G, H Notes, due 2025-2037 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	0
Laredo Ridge, due 2028
Debt Instrument [Line Items]
Long-term debt	$ 80	84
Laredo Ridge, due 2028 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.125%
Laredo Ridge, due 2028 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 10
Kansas South, due 2030
Debt Instrument [Line Items]
Long-term debt	$ 23	24
Kansas South, due 2030 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.25%
Kansas South, due 2030 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 2
Kawailoa Solar Holdings LLC, due 2026
Debt Instrument [Line Items]
Long-term debt	$ 82	82
Kawailoa Solar Holdings LLC, due 2026 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.375%
Kawailoa Solar Holdings LLC, due 2026 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 13
Marsh Landing, due 2023
Debt Instrument [Line Items]
Long-term debt	$ 164	206
Marsh Landing, due 2023 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.125%
Marsh Landing, due 2023 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 38
NIMH Solar, due 2024
Debt Instrument [Line Items]
Long-term debt	$ 193	0
NIMH Solar, due 2024 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.00%
NIMH Solar, due 2024 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 11
Oahu Solar Holdings LLC, due 2026
Debt Instrument [Line Items]
Long-term debt	$ 90	91
Oahu Solar Holdings LLC, due 2026 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.375%
Oahu Solar Holdings LLC, due 2026 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 11
Repowering Partnership Holdco LLC, due 2020
Debt Instrument [Line Items]
Long-term debt	$ 0	228
Repowering Partnership Holdco LLC, due 2020 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.85%
Repowering Partnership Holdco LLC, due 2020 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 0
South Trent, due 2028
Debt Instrument [Line Items]
Long-term debt	$ 39	43
South Trent, due 2028 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.35%
South Trent, due 2028 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 12
Tapestry, due 2031
Debt Instrument [Line Items]
Long-term debt	$ 147	156
Tapestry, due 2031 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.375%
Tapestry, due 2031 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 18
Utah Solar Holdings, due 2036
Debt Instrument [Line Items]
Long-term debt	$ 296	0
Debt instrument, basis spread on variable rate	3.59%
Utah Solar Holdings, due 2036 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 9
Utah Solar Portfolio, due 2022
Debt Instrument [Line Items]
Long-term debt	$ 0	254
Utah Solar Portfolio, due 2022 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.625%
Utah Solar Portfolio, due 2022 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 0
Viento, due 2023
Debt Instrument [Line Items]
Long-term debt	$ 35	42
Viento, due 2023 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.00%
Viento, due 2023 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 12
Walnut Creek, due 2023
Debt Instrument [Line Items]
Long-term debt	$ 140	175
Walnut Creek, due 2023 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%
Walnut Creek, due 2023 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 80
Other
Debt Instrument [Line Items]
Long-term debt	242	296
Other | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 29
Blythe
Debt Instrument [Line Items]
Long-term debt		14
Roadrunner
Debt Instrument [Line Items]
Long-term debt		$ 28