Other Comprehensive Income (Loss) - Changes in AOCI Balance by Component (Details) - USD ($) $ in Millions	3 Months Ended							6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023		Jun. 30, 2022		Mar. 31, 2022		Jun. 30, 2023
Other Comprehensive Income (Loss)
Income Before Reclassifications								$ 3
Amounts Reclassified to Net Earnings								10
Tax Expense								(15)
Total Other Comprehensive Income	$ (4)	$ 2		$ 39		$ 31		(2)
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								10
Tax Expense								(2)
Total Other Comprehensive Income								8
Balance June 30, 2023, Net of Tax	(489)							(489)
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								3
Amounts Reclassified to Net Earnings								0
Tax Expense								(13)
Total Other Comprehensive Income								(10)
Balance June 30, 2023, Net of Tax	140							140
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								0
Tax Expense								0
Total Other Comprehensive Income								0
Balance June 30, 2023, Net of Tax	(41)							(41)
Accumulated Other Comprehensive Income (Loss)
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	(4)	$ 2	[1]	$ 39	[1]	$ 31	[1]
Balance June 30, 2023, Net of Tax	$ (390)							$ (390)

[1] Accumulated Other Comprehensive Loss balances shown above are net of tax. The associated taxes were $99 million and $88 million as of first and second quarters 2022, respectively. For additional information, see Note 10, Other Comprehensive Income.