Employee Benefits (Schedule Of Change In Benefit Obligation and Change In Plan Assets) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) subsidiary	Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number Of Subsidiaries Company Provides Post Retirement Healthcare Benefit | subsidiary	2
Domestic Plan [Member]
Change in plan assets
Fair value of plan assets, beginning of year	$ 614
Fair value of plan assets, end of year	650	$ 614
Foreign Plan [Member]
Change in plan assets
Fair value of plan assets, beginning of year	16
Fair value of plan assets, end of year	18	16
Defined Benefit Plans [Member] | Domestic Plan [Member]
Change in benefit obligation
Benefit obligation, beginning of year	799	62
Benefit obligation assumed with acquisition	0	818
Service cost	3	1
Interest Cost	25	9
Actuarial loss (gain)	41	(74)
Benefits paid	(45)	(17)
Settlements	(16)	0
Foreign exchange effects	0	0
Benefit obligation, end of year	807	799
Change in plan assets
Fair value of plan assets, beginning of year	614	51
Acquisition	0	576
Actual return	97	7
Employer contribution	2	0
Benefits paid	(45)	(17)
Administrative expenses paid	(2)	(3)
Settlements	(16)	0
Foreign exchange effects	0	0
Fair value of plan assets, end of year	650	614
Funded status, end of year	(157)	(185)
Defined Benefit Plans [Member] | Foreign Plan [Member]
Change in benefit obligation
Benefit obligation, beginning of year	125	95
Benefit obligation assumed with acquisition	0	21
Service cost	2	1
Interest Cost	3	2
Actuarial loss (gain)	0	13
Benefits paid	(3)	(3)
Settlements	(1)	0
Foreign exchange effects	16	(4)
Benefit obligation, end of year	142	125
Change in plan assets
Fair value of plan assets, beginning of year	16	0
Acquisition	0	16
Actual return	1	0
Employer contribution	1	3
Benefits paid	0	(3)
Administrative expenses paid	0	0
Settlements	(1)	0
Foreign exchange effects	1	0
Fair value of plan assets, end of year	18	16
Funded status, end of year	(124)	(109)
Other Postretirement Plan Benefits [Member] | Domestic Plan [Member]
Change in benefit obligation
Benefit obligation, beginning of year	80	18
Benefit obligation assumed with acquisition	0	69
Service cost	1	0
Interest Cost	2	1
Actuarial loss (gain)	(1)	(6)
Benefits paid	(9)	(2)
Benefit obligation, end of year	73	80
Change in plan assets
Fair value of plan assets, beginning of year	0	0
Employer contribution	9	2
Plan participants' contributions	0	0
Benefits paid	(9)	(2)
Fair value of plan assets, end of year	0	0
Funded status, end of year	(73)	(80)
Other Postretirement Plan Benefits [Member] | Foreign Plan [Member]
Change in benefit obligation
Benefit obligation, beginning of year	3	0
Benefit obligation assumed with acquisition	0	3
Service cost	0	0
Interest Cost	0	0
Actuarial loss (gain)	0	0
Benefits paid	0	0
Benefit obligation, end of year	3	3
Change in plan assets
Fair value of plan assets, beginning of year	0	0
Employer contribution	0	0
Plan participants' contributions	0	0
Benefits paid	0	0
Fair value of plan assets, end of year	0	0
Funded status, end of year	$ (3)	$ (3)