CONTINGENCIES (Environmental Obligations) (Details) site in Thousands, $ in Millions		12 Months Ended
	Jan. 17, 2017 USD ($) site divisions	Dec. 31, 2019 USD ($) state project	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Site Contingency [Line Items]
Number of remediation projects | project		100
Number of US States with remediation projects | state		24
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of year		$ 1,511	$ 1,439	$ 1,221
Accretion Expense		102	100	84
Additionsb		23	56	241
Reductions		(1)	0	(43)
Spending		(74)	(84)	(64)
Balance at end of year		1,561	1,511	1,439
Less current portion		(106)	(132)	(134)
Long-term portion		1,455	$ 1,379	1,305
Estimated environmental cash payments (on an undiscounted and unescalated basis) [Abstract]
2020		106
2021		119
2022		95
2023		100
2024		100
Thereafter		2,700
Estimated environmental obligations on a discounted basis		1,400
Estimated environmental obligations on an undiscounted and unescalated		3,200
Environmental Loss Contingency, Number of Uranium Sites on Tribal Lands | divisions	94
Remediation work related to Uranium mines, amount to be contributed by the U.S. Government	$ 335
Uranium mine remediation work, program term, in years	20 years
Number of site surveys being performed to mining claims | site	10
Minimum
Estimated environmental cash payments (on an undiscounted and unescalated basis) [Abstract]
Estimated environmental obligations on an undiscounted and unescalated		2,700
Maximum
Estimated environmental cash payments (on an undiscounted and unescalated basis) [Abstract]
Estimated environmental obligations on an undiscounted and unescalated		3,700
Pinal Creek, AZ; Newtown Creek, NY; Smelter Sites in Arizona, Indiana, Kansas, Missouri, New Jersey, Oklahoma, Pennsylvania; and Uranium Mining in Wester United States
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at end of year		$ 1,400
Newtown Creek
Accrual for Environmental Loss Contingencies [Roll Forward]
Additionsb				138
Borough of Carteret
Accrual for Environmental Loss Contingencies [Roll Forward]
Additionsb				59
Uranium Mining Sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Reductions				$ (41)