CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income		$ 594	$ 208
Change in value of pension and other postretirement liabilities:
Amortization of prior service cost and net gain included in net periodic pension cost	[1]	0	0
Comprehensive income		$ 594	$ 208

[1] For the three months ended March 31, 2018, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.