RISK MANAGEMENT AND FINANCIAL INSTRUMENTS - Notional Principal or Quantity Information (Details) - Mar. 31, 2022 € in Millions, ¥ in Millions, £ in Millions, $ in Millions, $ in Millions	USD ($) MWh Bcf MMBbls	GBP (£) MWh Bcf MMBbls	EUR (€) MWh Bcf MMBbls	JPY (¥) MWh Bcf MMBbls	CAD ($) MWh Bcf MMBbls
Foreign exchange contracts - forwards - purchase | United States dollar
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022	$ 848
2023	0
2024	1,000
2025	500
2026	0
Thereafter	0
Derivative Notional Amount Outstanding	2,348
Foreign exchange contracts - forwards - purchase | Japanese yen
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022 | ¥				¥ 52,500
2023 | ¥				0
2024 | ¥				0
2025 | ¥				0
2026 | ¥				0
Thereafter | ¥				0
Derivative Notional Amount Outstanding | ¥				¥ 52,500
Foreign exchange contracts - forwards - sell | United States dollar
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022	7,544
2023	5,794
2024	4,544
2025	3,372
2026	2,772
Thereafter	492
Derivative Notional Amount Outstanding	$ 24,518
Foreign exchange contracts - forwards - sell | GBP
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022 | £		£ 21
2023 | £		29
2024 | £		30
2025 | £		30
2026 | £		28
Thereafter | £		32
Derivative Notional Amount Outstanding | £		£ 170
Foreign exchange contracts - forwards - sell | Euro
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022 | €			€ 95
2023 | €			92
2024 | €			91
2025 | €			86
2026 | €			85
Thereafter | €			343
Derivative Notional Amount Outstanding | €			€ 792
Interest rate contracts - short-term borrowings
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022					$ 536
2023					796
2024					128
2025					30
2026					26
Thereafter					64
Derivative Notional Amount Outstanding					1,580
Interest rate contracts - long-term debt pay fixed rate
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022					2,549
2023					2,587
2024					1,687
2025					562
2026					0
Thereafter					0
Derivative Notional Amount Outstanding					7,385
Equity contracts
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022					0
2023					26
2024					21
2025					0
2026					0
Thereafter					0
Derivative Notional Amount Outstanding					$ 47
Commodity contracts | Natural gas
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022 (bcf / mmbbls) | Bcf	172,000,000	172,000,000	172,000,000	172,000,000	172,000,000
2023 (bcf / mmbbls) | Bcf	33,000,000	33,000,000	33,000,000	33,000,000	33,000,000
2024 (bcf / mmbbls) | Bcf	13,000,000	13,000,000	13,000,000	13,000,000	13,000,000
2025 (bcf / mmbbls) | Bcf	11,000,000	11,000,000	11,000,000	11,000,000	11,000,000
2026 (bcf / mmbbls) | Bcf	0	0	0	0	0
Thereafter (bcf / mmbbls) | Bcf	0	0	0	0	0
Derivative Nonmonetary Notional Amount Outstanding | Bcf	229,000,000	229,000,000	229,000,000	229,000,000	229,000,000
Commodity contracts | Crude
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022 (bcf / mmbbls) | MMBbls	10,000,000	10,000,000	10,000,000	10,000,000	10,000,000
2023 (bcf / mmbbls) | MMBbls	(1,000,000)	(1,000,000)	(1,000,000)	(1,000,000)	(1,000,000)
2024 (bcf / mmbbls) | MMBbls	0	0	0	0	0
2025 (bcf / mmbbls) | MMBbls	0	0	0	0	0
2026 (bcf / mmbbls) | MMBbls	0	0	0	0	0
Thereafter (bcf / mmbbls) | MMBbls	0	0	0	0	0
Derivative Nonmonetary Notional Amount Outstanding | MMBbls	9,000,000	9,000,000	9,000,000	9,000,000	9,000,000
Net sell | Commodity contracts | Power
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
2022 (MWH) | MWh	(14,000,000)	(14,000,000)	(14,000,000)	(14,000,000)	(14,000,000)
2023 (MWH) | MWh	(43,000,000)	(43,000,000)	(43,000,000)	(43,000,000)	(43,000,000)
2024 (MWH) | MWh	(43,000,000)	(43,000,000)	(43,000,000)	(43,000,000)	(43,000,000)
2025 (MWH) | MWh	(43,000,000)	(43,000,000)	(43,000,000)	(43,000,000)	(43,000,000)
2026 (MWH) | MWh	0	0	0	0	0
Thereafter (MWH) | MWh	0	0	0	0	0
Total (MWH) | MWh	(37)	(37)	(37)	(37)	(37)