Pension and Other Postretirement Benefit Plans Pension and Other Postretirement Benefit Plans (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
International
Defined Benefit Plan Disclosure [Line Items]
Expected future employer contributions, current fiscal year	$ 375
Contributions by employer	123
U.S.
Defined Benefit Plan Disclosure [Line Items]
Expected future employer contributions, current fiscal year	200
Contributions by employer	$ 184