Pension Plan And Other Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended		12 Months Ended
		Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Mar. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (gain)		$ 4		$ 4	$ 20	$ 12
Net gain incurred in period	[1]	$ 1			5
Employer contributions					8
Company's expected additional annual contribution					$ 3
Common Stock in Treasury, Shares		31,269			31,269		47,149
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Non-cash curtailment gain (loss)			$ (1)		$ (1)
Settlement loss		$ (2)			(10)
Benefit obligation		$ 40			$ 40		$ 31
Discount rate		4.20%			4.20%			4.60%
Pension Benefits [Member] | One-time Termination Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Lump-sum payment		$ 35	$ 35
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Non-cash curtailment gain (loss)					$ 6
Net periodic benefit cost (gain)		1		$ 1	(4)	$ 3
Benefit obligation		$ 12			$ 12		$ 20
Discount rate		4.20%			4.20%			4.60%
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Common stock purchased under the terms of the Non-Qualified Plan presented as treasury stock					31,269		47,149

[1] Net of $1 million and $2 million in taxes for the three and nine months ended September 30, 2016, respectively.