Benefit Plans (Schedule Of Components Of Net Periodic Benefit Cost (Income)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 18	$ 22	$ 55	$ 65
Interest cost	70	84	211	252
Expected return on plan assets	(139)	(135)	(416)	(405)
Amortization of net loss	43	58	130	175
Amortization of prior service cost (credit)	2	2	4	6
Termination and curtailment	0	0	20	0
Net periodic benefit cost (income)	(6)	31	4	93
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4	12	13
Interest cost	18	24	58	75
Expected return on plan assets	0	0	0	0
Amortization of net loss	3	10	19	33
Amortization of prior service cost (credit)	(10)	(10)	(29)	(30)
Termination and curtailment	0	0	0	0
Net periodic benefit cost (income)	$ 15	$ 28	$ 60	$ 91