Defined Benefit Postretirement Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Amortization:
Net settlement loss	$ (3)	$ (5)	$ (6)	$ (9)
Estimated future contributions over the remainder of the current year	6		6
Funded Plan
Amortization:
Payment for pension benefits			6
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	3	7	7
Interest cost	3	2	6	4
Expected return on plan assets	(2)	(3)	(4)	(5)
Amortization:
– prior service credit	(1)	(1)	(3)	(3)
– actuarial loss	0	1	0	1
Net settlement loss	0	0	1	0
Net periodic benefit costs (credits)	4	2	7	4
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	0	1	1	1
Expected return on plan assets	0	0	0	0
Amortization:
– prior service credit	(4)	(4)	(8)	(8)
– actuarial loss	1	0	1	1
Net settlement loss	0	0	0	0
Net periodic benefit costs (credits)	$ (3)	$ (3)	(6)	$ (6)
Unfunded Portion of Pension Plan
Amortization:
Payment for pension and other postretirement benefits			3
Unfunded Portion of Other Postretirement Benefits Plan
Amortization:
Payment for pension and other postretirement benefits			$ 3