CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Comprehensive income:
Net income	$ 656	$ 649	$ 1,362	$ 1,357
Pension and retiree medical benefits:
Net pension and retiree medical losses arising during the period, net of tax of $—, $4, $— and $4, respectively	0	10	0	11
Reclassifications of loss to net income, net of tax of $—, $—, $— and $1, respectively	0	1	1	2
Derivative instruments:
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	3	0	11	15
Reclassification of losses to net income, net of tax of $—, $—, $1 and $1, respectively	1	1	3	4
Total other comprehensive income	4	12	15	32
Total comprehensive income	$ 660	$ 661	$ 1,377	$ 1,389