Retirement Benefits (Details 8)	12 Months Ended
Dec. 31, 2010	Dec. 31, 2009
Pension Benefits \| Benefit Obligation
Assumptions Used to Determine Benefit Obligation at December 31 [Abstract]
Discount rate	5.75%	6.03%
Rate of compensation increase	3.50%	3.75%
Pension Benefits \| Benefit Cost
Assumptions Used to Determine Benefit Obligation at December 31 [Abstract]
Discount rate	6.03%	6.25%
Expected long-term return on plan assets	8.50%	8.50%
Rate of compensation increase	3.75%	4.00%
Medical and Life Benefits \| Benefit Obligation
Assumptions Used to Determine Benefit Obligation at December 31 [Abstract]
Discount rate	5.62%	5.77%
Initial health care cost trend rate assumed for the next year	8.00%	7.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend date	2017	2014
Medical and Life Benefits \| Benefit Cost
Assumptions Used to Determine Benefit Obligation at December 31 [Abstract]
Initial health care cost trend rate assumed for the next year	7.00%	7.50%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend date	2014	2014
Discount rate	5.77%	6.25%
Expected long-term return on plan assets	6.90%	6.95%

The interest rate used to adjust for the time value of money for the plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph j

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- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
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- Definition

The interest rate used to adjust for the time value of money.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
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- Definition

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 264

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
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- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
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- Definition

The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
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The ultimate trend rate for health care costs.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
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- Definition

The year when the ultimate health care cost trend rate is expected to be reached.

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-Number 132R
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