Pension Plan And Other Postretirement Benefits (Pension And Other Postretirement Benefit Costs) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	$ 4		$ 4	$ 20	$ 12
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3		4	9	12
Interest cost	1		1	4	4
Expected return on plan assets	(2)		(2)	(5)	(6)
Amortization of prior service cost
Amortization of net loss			$ 1	1	$ 2
Curtailment loss		$ 1		1
Settlement loss	$ 2			$ 10