Retirement Benefits (Details 6) (USD $) In Millions	12 Months Ended
Dec. 31, 2010
Pension Benefits
Amounts Expected to be Recognized in 2011 Net Periodic Benefit Cost (Table Amounts) [Abstract]
Net loss	$ 161
Prior service cost (credit)	23
Medical and Life Benefits
Amounts Expected to be Recognized in 2011 Net Periodic Benefit Cost (Table Amounts) [Abstract]
Net loss	11
Prior service cost (credit)	$ (51)

The amounts in accumulated other comprehensive income related to gains and losses that are not recognized immediately and are expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7
-Subparagraph d

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration