Benefit Plans (Schedule Of Components Of Net Periodic Pension and Postretirement Costs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 19	$ 22	$ 37	$ 43
Interest cost	70	84	141	168
Expected return on plan assets	(139)	(135)	(277)	(270)
Amortization of net loss	43	58	87	117
Amortization of prior service cost (credit)	1	2	2	4
Termination and curtailment	0	0	20	0
Net periodic benefit cost (income)	(6)	31	10	62
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	5	8	9
Interest cost	19	25	40	51
Expected return on plan assets	0	0	0	0
Amortization of net loss	9	11	16	23
Amortization of prior service cost (credit)	(9)	(10)	(19)	(20)
Termination and curtailment	0	0	0	0
Net periodic benefit cost (income)	$ 23	$ 31	$ 45	$ 63