PENSION AND OTHER POST-EMPLOYMENT BENEFITS - Estimated Future Benefit Payments (Details) $ in Millions	Dec. 31, 2021 USD ($)
Pension
Estimated Future Benefit Payments
2022	$ 566
2023	575
2024	581
2025	590
2026	598
Years 2027-2030	3,075
OPEB
Estimated Future Benefit Payments
2022	44
2023	41
2024	39
2025	38
2026	37
Years 2027-2030	164
Subsidy Receipts
2022	(1)
2023	(1)
2024	(1)
2025	0
2026	0
Years 2027-2030	$ (2)

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