Stockholders' Equity (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
AOCI Attributable to Parent, Net of Tax
Accumulated other comprehensive income (loss) beginning balance	$ (1,970)	$ (1,608)
Other comprehensive loss before reclassifications	(64)	6
Reclassifications to net earnings	35	29
Other comprehensive income	(29)	35
Tax effects reclassified to retained earnings		(230)
Accumulated other comprehensive income (loss) ending balance	(1,999)	(1,803)
Tax provision on net actuarial gain (loss) and prior service costs related to pension and other postretirement benefit plans	11	10
Cumulative Translation Adjustments [Member]
AOCI Attributable to Parent, Net of Tax
Accumulated other comprehensive income (loss) beginning balance	(463)	(476)
Other comprehensive loss before reclassifications	(64)	6
Reclassifications to net earnings	0	0
Other comprehensive income	(64)	6
Tax effects reclassified to retained earnings		0
Accumulated other comprehensive income (loss) ending balance	(527)	(470)
Net Actuarial Loss and Prior Service Cost [Member]
AOCI Attributable to Parent, Net of Tax
Accumulated other comprehensive income (loss) beginning balance	(1,507)	(1,132)
Other comprehensive loss before reclassifications	0	0
Reclassifications to net earnings	35	29
Other comprehensive income	35	29
Tax effects reclassified to retained earnings		(230)
Accumulated other comprehensive income (loss) ending balance	$ (1,472)	$ (1,333)