Retirement Benefits (Fair Values Of Company's Other Postretirement Benefit Plan Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Fair values of other postretirement benefit plan assets	$ 205	$ 234
Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of other postretirement benefit plan assets	4	4
Unitized Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of other postretirement benefit plan assets	201	230
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of other postretirement benefit plan assets	4	4
Level 1 [Member] | Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of other postretirement benefit plan assets	4	4
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of other postretirement benefit plan assets	201	230
Level 2 [Member] | Unitized Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of other postretirement benefit plan assets	$ 201	$ 230