New And Significant Accounting Policies (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost for benefits earned		$ 113	$ 123	$ 339	$ 360
Interest cost		179	168	537	505
Expected return on plan assets		(207)	(219)	(621)	(655)
Amortization of prior service cost		2	4	6	11
Amortization of net actuarial loss		6	1	18	7
Net periodic benefit cost		93	77	279	228
Regulatory account transfer	[1]	(8)	8	(25)	26
Total		85	85	254	254
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost for benefits earned		13	14	39	41
Interest cost		19	18	57	54
Expected return on plan assets		(26)	(28)	(80)	(84)
Amortization of prior service cost		3	4	11	14
Amortization of net actuarial loss		1	1	3	3
Net periodic benefit cost		10	9	30	28
Regulatory account transfer	[1]	0	0	0	0
Total		$ 10	$ 9	$ 30	$ 28

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