Long-term Debt - Debt Table (Details) - USD ($) $ in Millions | 3 Months Ended | | |
Mar. 31, 2019 | Dec. 31, 2018 | May 31, 2018 |
Debt Instrument [Line Items] | | | |
Long-term debt — affiliate | $ 44 | $ 44 | |
Long-term Debt | 5,886 | 6,038 | |
Current portion of long-term debt — external | (1,608) | (529) | |
Deferred Finance Costs, Net | (62) | (61) | |
Long-term Debt, Excluding Current Maturities | 4,216 | 5,448 | |
Intercompany Credit Agreement due 2019 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term debt — affiliate | $ 0 | 215 | |
Debt Instrument, Interest Rate, Stated Percentage | 3.58% | | |
Intercompany Credit Agreement due 2020 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term debt — affiliate | $ 44 | 44 | |
Debt Instrument, Interest Rate, Stated Percentage | 3.325% | | |
5.375% Senior Notes due in 2024 [Member] | | | |
Debt Instrument [Line Items] | | | |
Senior Notes | $ 500 | 500 | |
Debt Instrument, Interest Rate, Stated Percentage | 5.375% | | |
5.75% Senior Notes due 2025 [Member] | | | |
Debt Instrument [Line Items] | | | |
Senior Notes | $ 600 | 600 | |
Debt Instrument, Interest Rate, Stated Percentage | 5.75% | | |
5.00% Senior Notes due in 2026 [Member] | | | |
Debt Instrument [Line Items] | | | |
Senior Notes | $ 350 | 350 | |
Debt Instrument, Interest Rate, Stated Percentage | 5.00% | | |
Revolving Credit Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 0 | 0 | |
Debt Instrument, Description of Variable Rate Basis | 3 month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 1.75% | | |
Agua Caliente Borrower 2 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 38 | 39 | |
Debt Instrument, Interest Rate, Stated Percentage | 5.43% | | |
Alpine Financing Agreement, due 2022 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 127 | 127 | |
Debt Instrument, Description of Variable Rate Basis | 3-Month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 1.75% | | |
Alta Wind I-V, lease financing arrangement, due 2034 and 2035 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 886 | 886 | |
Buckthorn Solar, due 2025 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 131 | 132 | $ 132 |
Debt Instrument, Description of Variable Rate Basis | 1-Month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 1.75% | | |
CVSR Financing Agreement [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 702 | 720 | |
CVSR Holdco due 2037 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 184 | 188 | |
Debt Instrument, Interest Rate, Stated Percentage | 4.68% | | |
El Segundo Energy Center, due 2023 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 320 | 352 | |
Debt Instrument, Description of Variable Rate Basis | 3-Month LIBOR | | |
El Segundo Energy Center, due 2023 Tranche B [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Basis Spread on Variable Rate | 2.375% | | |
El Segundo Energy Center, due 2023 Tranche A [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Basis Spread on Variable Rate | 1.75% | | |
Energy Center Minneapolis Series C Notes [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 328 | 328 | |
Laredo Ridge Wind, LLC, due in 2026 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 88 | 89 | |
Debt Instrument, Description of Variable Rate Basis | 3-Month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 1.875% | | |
Kansas South, due in 2030 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 26 | 26 | |
Debt Instrument, Description of Variable Rate Basis | 3-Month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 2.00% | | |
Marsh Landing Term Loan Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 254 | 263 | |
Debt Instrument, Description of Variable Rate Basis | 3-Month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 2.125% | | |
Oahu Solar Holdings LLC, due 2026 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 147 | 0 | |
Debt Instrument, Description of Variable Rate Basis | 3-Month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 1.375% | | |
South Trent Wind Due 2020 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 49 | 50 | |
Debt Instrument, Description of Variable Rate Basis | 3-Month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 1.625% | | |
Tapestry Wind LLC due in 2021 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 147 | 151 | |
Debt Instrument, Description of Variable Rate Basis | 3-Month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 1.75% | | |
Utah Solar Portfolio, due 2022 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 267 | 267 | |
Viento Funding II, Inc., due in 2023 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 146 | 146 | |
Debt Instrument, Description of Variable Rate Basis | 3-Month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 2.00% | | |
Walnut Creek Energy, LLC, due in 2023 [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 214 | 222 | |
Debt Instrument, Description of Variable Rate Basis | 3-Month LIBOR | | |
Debt Instrument, Basis Spread on Variable Rate | 1.75% | | |
Other Debt [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | $ 338 | 343 | |
Project Level Debt [Member] | | | |
Debt Instrument [Line Items] | | | |
Long-term Debt | 4,392 | $ 4,329 | |
Letter of Credit [Member] | Revolving Credit Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 41 | | |
Letter of Credit [Member] | Agua Caliente Borrower 2 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 17 | | |
Letter of Credit [Member] | Alpine Financing Agreement, due 2022 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 16 | | |
Letter of Credit [Member] | Alta Wind I-V, lease financing arrangement, due 2034 and 2035 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 44 | | |
Letter of Credit [Member] | Buckthorn Solar, due 2025 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 26 | | |
Letter of Credit [Member] | CVSR Financing Agreement [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 0 | | |
Letter of Credit [Member] | CVSR Holdco due 2037 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 13 | | |
Letter of Credit [Member] | El Segundo Energy Center, due 2023 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 138 | | |
Letter of Credit [Member] | Energy Center Minneapolis Series C Notes [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 0 | | |
Letter of Credit [Member] | Laredo Ridge Wind, LLC, due in 2026 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 10 | | |
Letter of Credit [Member] | Kansas South, due in 2030 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 2 | | |
Letter of Credit [Member] | Marsh Landing Term Loan Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 29 | | |
Letter of Credit [Member] | Oahu Solar Holdings LLC, due 2026 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 10 | | |
Letter of Credit [Member] | South Trent Wind Due 2020 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 10 | | |
Letter of Credit [Member] | Tapestry Wind LLC due in 2021 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 20 | | |
Letter of Credit [Member] | Utah Solar Portfolio, due 2022 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 13 | | |
Letter of Credit [Member] | Viento Funding II, Inc., due in 2023 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 27 | | |
Letter of Credit [Member] | Walnut Creek Energy, LLC, due in 2023 [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | 85 | | |
Letter of Credit [Member] | Other Debt [Member] | | | |
Debt Instrument [Line Items] | | | |
Letters of Credit Outstanding, Amount | $ 24 | | |
Minimum [Member] | Alta Wind I-V, lease financing arrangement, due 2034 and 2035 [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Interest Rate, Stated Percentage | 5.696% | | |
Minimum [Member] | CVSR Financing Agreement [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Interest Rate, Stated Percentage | 2.339% | | |
Maximum [Member] | Alta Wind I-V, lease financing arrangement, due 2034 and 2035 [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Interest Rate, Stated Percentage | 7.015% | | |
Maximum [Member] | CVSR Financing Agreement [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Interest Rate, Stated Percentage | 3.775% | | |
London Interbank Offered Rate (LIBOR) [Member] | Kansas South, due in 2030 [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Basis Spread on Variable Rate | 2.00% | | |
London Interbank Offered Rate (LIBOR) [Member] | Utah Solar Portfolio, due 2022 [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Basis Spread on Variable Rate | 2.625% | | |