Benefit Plans (Pension and Postretirement Liabilities Recognized in Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Other assets	$ 43	$ 37
Accrued liabilities — employment costs	(23)	(20)
Long-term employment costs	(2,704)	(2,281)
Net benefit liability	(2,684)	(2,264)
Postretirement [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued liabilities — employment costs	(8)	(10)
Long-term employment costs	(182)	(199)
Net benefit liability	$ (190)	$ (209)