Retirement Benefits (Components Of Net Periodic Benefit Cost) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Pension Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 23		$ 20		$ 69		$ 61
Interest cost	40		42		121		125
Expected return on plan assets	(54)		(52)		(162)		(156)
Transition obligation
Prior service cost (benefit)	(1)		(1)		(3)		(3)
Actuarial loss	23		19		69		56
Net periodic benefit cost	31	[1]	28	[1]	94	[1]	83	[1]
Postretirement Benefit Costs [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	6		5		17		16
Interest cost	11		12		34		36
Expected return on plan assets	(16)		(14)		(47)		(42)
Transition obligation			1				1
Prior service cost (benefit)	(1)		(1)		(3)		(3)
Actuarial loss	2		1		6		3
Net periodic benefit cost	$ 2	[1]	$ 4	[1]	$ 7	[1]	$ 11	[1]

[1] Excludes the EEI plans as they are included in discontinued operations.