Other Comprehensive Income (Loss) - Changes in AOCI balance by Component (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Other Comprehensive Income (Loss)
Loss Before Reclassifications		$ (7)
Amounts Reclassified to Net Earnings		11
Tax (Expense) Benefit		(1)
Total Other Comprehensive Income (Loss)		3	$ 2
Pension and Other Post-Employment Benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance December 31, 2019, Net of Tax		(619)
Other Comprehensive Income (Loss)
Loss Before Reclassifications		0
Amounts Reclassified to Net Earnings		14
Tax (Expense) Benefit		(2)
Total Other Comprehensive Income (Loss)		12
Balance March 31, 2020, Net of Tax		(607)
Other
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance December 31, 2019, Net of Tax		(56)
Other Comprehensive Income (Loss)
Loss Before Reclassifications		(7)
Amounts Reclassified to Net Earnings		(3)
Tax (Expense) Benefit		1
Total Other Comprehensive Income (Loss)		(9)
Balance March 31, 2020, Net of Tax		(65)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance December 31, 2019, Net of Tax		(675)
Other Comprehensive Income (Loss)
Total Other Comprehensive Income (Loss)	[1]	3	$ 2
Balance March 31, 2020, Net of Tax		$ (672)

[1] (a) Accumulated Other Comprehensive Loss balances shown above are net of tax. The associated taxes were $183 million and $179 million as of March 31, 2020 and March 31, 2019, respectively. For additional information, see Note 12, Other Comprehensive Income.