Employee Benefit Plans (Changes In Defined Benefit Obligation And Fair Value Of Defined Benefit Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning	$ 2,018
Fair value of plan assets, ending	2,337	$ 2,018
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation, beginning	2,650	2,323
Service cost	61	58	$ 66
Interest cost	70	82	93
Actuarial loss (gain)	285	363
Employee contributions	2	2
Settlements	(17)	35	(528)
Defined Benefit Plan, Benefit Obligation, Business Combination	0	26
Benefits paid	(84)	(249)
Plan Amendments	0	(2)
Foreign currency effects	47	12
Benefit obligation, ending	3,014	2,650	2,323
Fair value of plan assets, beginning	2,018	1,736
Actual return on plan assets	317	348
Employer contributions	85	166
Employee contributions	2	2
Settlements	(18)	(10)
Defined Benefit Plan, Plan Assets, Business Combination	0	7
Benefits Paid	(84)	(249)
Foreign currency effects	17	18
Fair value of plan assets, ending	2,337	2,018	1,736
Funded status	(677)	(632)
Prepaid benefit cost	29	38
Accrued benefit liability - current	(19)	(18)
Accrued benefit liability - long-term	(687)	(652)
Net amount recognized in the balance sheet	(677)	(632)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation, beginning	167	144
Service cost	1	2	2
Interest cost	4	5	5
Actuarial loss (gain)	17	24
Settlements	0	3
Defined Benefit Plan, Benefit Obligation, Business Combination	0	3
Benefits paid	(14)	(14)
Plan Amendments	0	0
Foreign currency effects	(2)	0
Benefit obligation, ending	173	167	$ 144
Fair value of plan assets, beginning	0
Employer contributions	14	14
Defined Benefit Plan, Plan Assets, Business Combination	0	0
Benefits Paid	(14)	(14)
Fair value of plan assets, ending	0	0
Funded status	(173)	(167)
Accrued benefit liability - current	(16)	(16)
Accrued benefit liability - long-term	(157)	(151)
Net amount recognized in the balance sheet	$ (173)	$ (167)