Equity and Comprehensive Earnings - AOCI Activity (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021
Accumulated Other Comprehensive Earnings (Loss)
Stockholders' Equity Attributable to Parent, Beginning Balance		$ 3,275
Stockholders' Equity Attributable to Parent, Ending Balance	$ 3,704	3,704
Settlement loss	130
Foreign Currency Translation
Accumulated Other Comprehensive Earnings (Loss)
Stockholders' Equity Attributable to Parent, Beginning Balance		(555)
Other comprehensive earnings (loss) before reclassifications		19
Stockholders' Equity Attributable to Parent, Ending Balance	(536)	(536)
Pension and Other Postretirement Benefits (Net of Tax)
Accumulated Other Comprehensive Earnings (Loss)
Stockholders' Equity Attributable to Parent, Beginning Balance		(466)
Other comprehensive earnings (loss) before reclassifications		55
Reclassification of net deferred (gains) losses into earnings		129
Stockholders' Equity Attributable to Parent, Ending Balance	(282)	(282)
Effective Derivatives (Net of Tax)
Accumulated Other Comprehensive Earnings (Loss)
Stockholders' Equity Attributable to Parent, Beginning Balance		67
Other comprehensive earnings (loss) before reclassifications		159
Reclassification of net deferred (gains) losses into earnings		(61)
Stockholders' Equity Attributable to Parent, Ending Balance	165	165
Accumulated Other Comprehensive Earnings (Loss).
Accumulated Other Comprehensive Earnings (Loss)
Stockholders' Equity Attributable to Parent, Beginning Balance		(954)
Other comprehensive earnings (loss) before reclassifications		233
Reclassification of net deferred (gains) losses into earnings		68
Stockholders' Equity Attributable to Parent, Ending Balance	$ (653)	$ (653)