Other Comprehensive Income (Loss) - Changes in AOCI Balance by Component (Details) - USD ($) $ in Millions	3 Months Ended									9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023		Sep. 30, 2022	Jun. 30, 2022		Mar. 31, 2022		Sep. 30, 2023
Other Comprehensive Income (Loss)
Income Before Reclassifications										$ 22
Amounts Reclassified to Net Earnings										14
Tax Expense										(20)
Total Other Comprehensive Income	$ 18	$ (4)	$ 2		$ 18	$ 39		$ 31		16
Pension and Other Post-Employment Benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance December 31, 2022, Net of Tax			(497)							(497)
Other Comprehensive Income (Loss)
Income Before Reclassifications										0
Amounts Reclassified to Net Earnings										15
Tax Expense										(3)
Total Other Comprehensive Income										12
Balance September 30, 2023, Net of Tax	(485)									(485)
Interest Rate Derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance December 31, 2022, Net of Tax			150							150
Other Comprehensive Income (Loss)
Income Before Reclassifications										22
Amounts Reclassified to Net Earnings										0
Tax Expense										(18)
Total Other Comprehensive Income										4
Balance September 30, 2023, Net of Tax	154									154
Other
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance December 31, 2022, Net of Tax			(41)							(41)
Other Comprehensive Income (Loss)
Income Before Reclassifications										0
Amounts Reclassified to Net Earnings										(1)
Tax Expense										1
Total Other Comprehensive Income										0
Balance September 30, 2023, Net of Tax	(41)									(41)
Accumulated Other Comprehensive (Loss) Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance December 31, 2022, Net of Tax			(388)							(388)
Other Comprehensive Income (Loss)
Total Other Comprehensive Income	18	$ (4)	$ 2	[1]	$ 18	$ 39	[1]	$ 31	[1]
Balance September 30, 2023, Net of Tax	$ (372)									$ (372)

[1] Accumulated Other Comprehensive Loss balances shown above are net of tax. The associated taxes were $107 million as of December 31, 2021, $99 million as of March 31, 2022, $88 million as of June 30, 2022, and $85 million as of September 30, 2022. For additional information, see Note 10, Other Comprehensive Income.