CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Comprehensive income:
Net income	$ 1,736	$ 1,597	$ 1,473
Pension and retiree medical benefits:
Net pension and retiree medical gains (losses) arising during the period, net of tax of $1, $— and $(2), respectively	5	0	(5)
Reclassification of losses to net income, net of tax of $1, $3 and $3, respectively	(4)	(8)	(10)
Derivative instruments:
Net fair value increase (decrease), net of tax of $6, $1 and $(3), respectively	16	4	(10)
Reclassification of losses to net income, net of tax of $2, $2 and $2, respectively	(5)	(6)	(5)
Total other comprehensive income	30	18
Total comprehensive income	$ 1,766	$ 1,615	$ 1,473