New And Significant Accounting Policies (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost for benefits earned		$ 113	$ 119
Interest cost		179	168
Expected return on plan assets		(207)	(218)
Amortization of prior service cost		2	4
Amortization of net actuarial loss		6	3
Net periodic benefit cost		93	76
Less: transfer to regulatory account	[1]	(8)	9
Total		85	85
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost for benefits earned		13	13
Interest cost		19	18
Expected return on plan assets		(27)	(28)
Amortization of prior service cost		4	5
Amortization of net actuarial loss		1	1
Net periodic benefit cost		10	9
Less: transfer to regulatory account	[1]	0	0
Total		$ 10	$ 9

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