Accumulated Other Comprehensive Income (Loss) - After-tax Changes by Component (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (161)	$ (123)	$ (163)	$ (124)
Amounts arising during the period	2	(15)	3	(14)
Reclassifications from AOCI	(1)	1	0	1
Net OCI during the period	1	(14)	3	(13)
Balance at end of period	(160)	(137)	(160)	(137)
Unrealized gains (losses) on qualifying derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	7	4	6	3
Amounts arising during the period	0	0	0	0
Reclassifications from AOCI	0	0	1	1
Net OCI during the period	0	0	1	1
Balance at end of period	7	4	7	4
Equity Investees' OCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	4	3	3	2
Amounts arising during the period	0	0	1	1
Reclassifications from AOCI	0	0	0	0
Net OCI during the period	0	0	1	1
Balance at end of period	4	3	4	3
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(168)	(125)	(168)	(124)
Amounts arising during the period	2	(15)	2	(15)
Reclassifications from AOCI	(1)	0	(1)	(1)
Net OCI during the period	1	(15)	1	(16)
Balance at end of period	(167)	(140)	(167)	(140)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(4)	(5)	(4)	(5)
Amounts arising during the period	0	0	0	0
Reclassifications from AOCI	0	1	0	1
Net OCI during the period	0	1	0	1
Balance at end of period	$ (4)	$ (4)	$ (4)	$ (4)