PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($) $ in Millions	2 Months Ended	3 Months Ended		6 Months Ended
	Feb. 28, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay				5.00%
Qualified Plan
Defined Benefit Plan, Plan Assets, Contributions by Employer				$ 545
Automatic Non-Elective Contribution
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay				4.00%
Defined Benefit Pension Plans [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer				$ 548
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year		$ 550		550
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ 87
Increase (Decrease) in Obligation, Pension Benefits	(14)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	$ 7	0	$ 0	7	$ 0
Service cost		6	8	14	17
Interest cost		21	28	40	56
Defined Benefit Plan, Expected Return (Loss) on Plan Assets		56	50	107	100
Defined Benefit Plan, Amortization of Gain (Loss)		(28)	(27)	(58)	(54)
Net periodic benefit cost		(1)	13	(2)	27
Other Postretirement Benefits [Member]
Service cost		0	1	0	1
Interest cost		1	2	2	3
Defined Benefit Plan, Amortization of Gain (Loss)		1	2	2	3
Net periodic benefit cost		$ 0	$ 1	$ 0	$ 1