Pension And Other Postretirement Benefits (Schedule Of Estimated Benefit Payments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2012	$ 126
2013	125
2014	129
2015	133
2016	137
2017 through 2021	732
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2012	47
2013	49
2014	50
2015	52
2016	52
2017 through 2021	261
Expected Medicare Part D Subsidiaries [Member]
Defined Benefit Plan Disclosure [Line Items]
2012	2
2013	2
2014	3
2015	3
2016	3
2017 through 2021	$ 15