Other Comprehensive Income (Loss) - Changes in AOCI balance by Component (Details) $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($)
Other Comprehensive Income (Loss)
Loss Before Reclassifications	$ (1)
Amounts Reclassified to Net Earnings	17
Tax (Expense) Benefit	(4)
Reclassification of Stranded Tax Effects	(107)
Total Other Comprehensive Loss	(95)
Pension and Other Post-Employment Benefits
Other Comprehensive Income (Loss)
Beginning balance	(440)
Loss Before Reclassifications	0
Amounts Reclassified to Net Earnings	20
Tax (Expense) Benefit	(5)
Reclassification of Stranded Tax Effects	(108)
Total Other Comprehensive Loss	(93)
Ending balance	(533)
Other
Other Comprehensive Income (Loss)
Beginning balance	(46)
Loss Before Reclassifications	(1)
Amounts Reclassified to Net Earnings	(3)
Tax (Expense) Benefit	1
Reclassification of Stranded Tax Effects	1
Total Other Comprehensive Loss	(2)
Ending balance	(48)
Accumulated Other Comprehensive Income (Loss)
Other Comprehensive Income (Loss)
Beginning balance	(486)
Ending balance	$ (581)