RECLASSIFICATIONS FROM ACCUMULATED OTHER COMPREHENSIVE INCOME - Table (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Mar. 22, 2021
Reclassifications from accumulated other comprehensive (loss) income
Actuarial losses, net and prior service cost		$ 110	$ 104	$ 717
Tax expense (benefit)		278	288	210
Net of tax		(960)	(905)	(478)
Interest rate swaps		106	108	278
Disproportionate tax expense	$ 11
5.95 Notes and Debentures Due March 15, 2022
Reclassifications from accumulated other comprehensive (loss) income
Interest rate (as a percent)					5.95%
Amount reclassified
Reclassifications from accumulated other comprehensive (loss) income
Settlement loss				447
Tax expense (benefit)	(96)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Including Portion Attributable to Noncontrolling Interest | Amount reclassified
Reclassifications from accumulated other comprehensive (loss) income
Actuarial losses, net and prior service cost		1	6	18
Settlement loss	447	0	0	451
Tax expense (benefit)		0	(2)	(104)
Net of tax		1	4	365
Hüppe | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent | Amount reclassified
Reclassifications from accumulated other comprehensive (loss) income
Actuarial losses, net and prior service cost	$ 3
Interest Rate Swaps | Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest | Amount reclassified
Reclassifications from accumulated other comprehensive (loss) income
Tax expense (benefit)		0	0	5
Net of tax		0	0	7
Interest rate swaps		$ 0	$ 0	$ 2