Other Comprehensive Income (Loss) - Changes in AOCI balance by Component (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Other Comprehensive Income (Loss)
Loss Before Reclassifications		$ (2)
Amounts Reclassified to Net Earnings		6
Tax Expense		(2)
Total Other Comprehensive Income (Loss)		2	$ (99)
Pension and Other Post-Employment Benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(604)
Other Comprehensive Income (Loss)
Loss Before Reclassifications		0
Amounts Reclassified to Net Earnings		6
Tax Expense		(1)
Total Other Comprehensive Income (Loss)		5
Ending balance		(599)
Other
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(57)
Other Comprehensive Income (Loss)
Loss Before Reclassifications		(2)
Amounts Reclassified to Net Earnings		0
Tax Expense		(1)
Total Other Comprehensive Income (Loss)		(3)
Ending balance		(60)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(661)
Other Comprehensive Income (Loss)
Total Other Comprehensive Income (Loss)	[1]	2	$ (99)
Ending balance		$ (659)

[1] Accumulated Other Comprehensive Loss balances shown above are net of tax. The associated taxes were $179 million and $160 million as of March 31, 2019 and March 31, 2018, respectively. For additional information, see Note 12, Other Comprehensive Income.