Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 309	$ 312	$ 383	$ 632
OTHER COMPREHENSIVE INCOME (LOSS):
Pension and OPEB prior service costs	(4)	(7)	(27)	(14)
Amortized losses on derivative hedges	1	0	1	1
Other comprehensive loss	(3)	(7)	(26)	(13)
Income tax benefits on other comprehensive loss	(1)	(2)	(6)	(3)
Other comprehensive loss, net of tax	(2)	(5)	(20)	(10)
COMPREHENSIVE INCOME	$ 307	$ 307	$ 363	$ 622