Employee Benefit Plans (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 55	$ 45	$ 53
Interest cost		71	76	74
Expected return on plan assets		(112)	(103)	(79)
Amortization of prior service cost		19	23	23
Amortization of net actuarial loss		4	2	6
Net periodic benefit cost		37	43	77
Pension Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		479	383	468
Interest cost		673	695	627
Expected return on plan assets		(873)	(807)	(650)
Amortization of prior service cost		15	20	20
Amortization of net actuarial loss		10	2	111
Net periodic benefit cost		304	293	576
Less: transfer to regulatory account	[1]	34	42	(238)
Total		$ 338	$ 335	$ 338

[1] The Utility recorded these amounts to a regulatory account as they are probable of recovery from customers in future rates.