New And Significant Accounting Policies (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost for benefits earned		$ 113	$ 118	$ 226	$ 237
Interest cost		179	169	358	337
Expected return on plan assets		(207)	(218)	(414)	(436)
Amortization of prior service cost		2	3	4	7
Amortization of net actuarial loss		6	3	12	6
Net periodic benefit cost		93	75	186	151
Less: transfer to regulatory account	[1]	(8)	9	(17)	18
Total		85	84	169	169
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost for benefits earned		13	14	26	27
Interest cost		19	18	38	36
Expected return on plan assets		(27)	(28)	(54)	(56)
Amortization of prior service cost		4	5	8	10
Amortization of net actuarial loss		1	1	2	2
Net periodic benefit cost		10	10	20	19
Less: transfer to regulatory account	[1]	0	0	0	0
Total		$ 10	$ 10	$ 20	$ 19

[1] The Utility recorded these amounts to a regulatory account since they are probable of recovery from, or refund to, customers in futures rates.