Retirement Benefits (Schedule Of Fair Values Of Pension Plan Assets By Asset Category) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended																																																																																																																																																12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Cash And Cash Equivalents [Member]	Dec. 31, 2010 Cash And Cash Equivalents [Member]	Dec. 31, 2011 International Markets [Member]		Dec. 31, 2010 International Markets [Member]		Dec. 31, 2011 Large-Cap Companies [Member]		Dec. 31, 2010 Large-Cap Companies [Member]		Dec. 31, 2011 Mid-Cap Companies [Member]		Dec. 31, 2010 Mid-Cap Companies [Member]		Dec. 31, 2011 Small-Cap Companies [Member]		Dec. 31, 2010 Small-Cap Companies [Member]		Dec. 31, 2011 Corporate Bonds [Member]		Dec. 31, 2010 Corporate Bonds [Member]		Dec. 31, 2011 Government Securities [Member]		Dec. 31, 2010 Government Securities [Member]		Dec. 31, 2011 U.S. Municipal Securities [Member]	Dec. 31, 2010 U.S. Municipal Securities [Member]	Dec. 31, 2011 Private Equity Partnerships [Member]		Dec. 31, 2010 Private Equity Partnerships [Member]		Dec. 31, 2009 Private Equity Partnerships [Member]	Dec. 31, 2011 Common/Collective And 103-12 Investment Trusts [Member]		Dec. 31, 2010 Common/Collective And 103-12 Investment Trusts [Member]		Dec. 31, 2010 Interest Rate Swap Contracts [Member]		Dec. 31, 2011 Insurance Group Annuity Contracts [Member]	Dec. 31, 2010 Insurance Group Annuity Contracts [Member]	Dec. 31, 2009 Insurance Group Annuity Contracts [Member]	Dec. 31, 2011 Dividend And Interest Receivable [Member]	Dec. 31, 2010 Dividend And Interest Receivable [Member]	Dec. 31, 2011 Due To/From Brokers For Sale Of Securities [Member]	Dec. 31, 2010 Due To/From Brokers For Sale Of Securities [Member]	Dec. 31, 2010 Swap Income Receivable [Member]	Dec. 31, 2011 Other Assets [Member]	Dec. 31, 2010 Other Assets [Member]	Dec. 31, 2011 Level 1 [Member]	Dec. 31, 2010 Level 1 [Member]	Dec. 31, 2011 Level 1 [Member] Cash And Cash Equivalents [Member]	Dec. 31, 2010 Level 1 [Member] Cash And Cash Equivalents [Member]	Dec. 31, 2011 Level 1 [Member] International Markets [Member]		Dec. 31, 2010 Level 1 [Member] International Markets [Member]		Dec. 31, 2011 Level 1 [Member] Large-Cap Companies [Member]		Dec. 31, 2010 Level 1 [Member] Large-Cap Companies [Member]		Dec. 31, 2011 Level 1 [Member] Mid-Cap Companies [Member]		Dec. 31, 2010 Level 1 [Member] Mid-Cap Companies [Member]		Dec. 31, 2011 Level 1 [Member] Small-Cap Companies [Member]		Dec. 31, 2010 Level 1 [Member] Small-Cap Companies [Member]		Dec. 31, 2011 Level 1 [Member] Dividend And Interest Receivable [Member]	Dec. 31, 2010 Level 1 [Member] Dividend And Interest Receivable [Member]	Dec. 31, 2011 Level 1 [Member] Due To/From Brokers For Sale Of Securities [Member]	Dec. 31, 2010 Level 1 [Member] Due To/From Brokers For Sale Of Securities [Member]	Dec. 31, 2010 Level 1 [Member] Swap Income Receivable [Member]	Dec. 31, 2011 Level 1 [Member] Other Assets [Member]	Dec. 31, 2010 Level 1 [Member] Other Assets [Member]	Dec. 31, 2011 Level 2 [Member]	Dec. 31, 2010 Level 2 [Member]	Dec. 31, 2011 Level 2 [Member] Corporate Bonds [Member]		Dec. 31, 2010 Level 2 [Member] Corporate Bonds [Member]		Dec. 31, 2011 Level 2 [Member] Government Securities [Member]		Dec. 31, 2010 Level 2 [Member] Government Securities [Member]		Dec. 31, 2011 Level 2 [Member] U.S. Municipal Securities [Member]	Dec. 31, 2010 Level 2 [Member] U.S. Municipal Securities [Member]	Dec. 31, 2011 Level 2 [Member] Common/Collective And 103-12 Investment Trusts [Member]		Dec. 31, 2010 Level 2 [Member] Common/Collective And 103-12 Investment Trusts [Member]		Dec. 31, 2010 Level 2 [Member] Interest Rate Swap Contracts [Member]		Dec. 31, 2011 Level 3 [Member]	Dec. 31, 2010 Level 3 [Member]	Dec. 31, 2011 Level 3 [Member] Private Equity Partnerships [Member]		Dec. 31, 2010 Level 3 [Member] Private Equity Partnerships [Member]		Dec. 31, 2011 Level 3 [Member] Insurance Group Annuity Contracts [Member]	Dec. 31, 2010 Level 3 [Member] Insurance Group Annuity Contracts [Member]	Dec. 31, 2011 United Kingdom [Member]	Dec. 31, 2010 United Kingdom [Member]	Dec. 31, 2011 Japan [Member]	Dec. 31, 2010 Japan [Member]	Dec. 31, 2011 Netherlands [Member]	Dec. 31, 2010 Netherlands [Member]	Dec. 31, 2011 Germany [Member]	Dec. 31, 2010 Germany [Member]	Dec. 31, 2011 France [Member]	Dec. 31, 2010 France [Member]	Dec. 31, 2011 Switzerland [Member]	Dec. 31, 2010 Switzerland [Member]	Dec. 31, 2011 Emerging Markets [Member]	Dec. 31, 2010 Emerging Markets [Member]	Dec. 31, 2011 No Concentration Greater Than Five Percent In Any One Country [Member]	Dec. 31, 2010 No Concentration Greater Than Five Percent In Any One Country [Member]	Dec. 31, 2011 Corporate Debt With Standard And Poor's (S&P) Rating Lower Than A [Member]	Dec. 31, 2010 Corporate Debt With Standard And Poor's (S&P) Rating Lower Than A [Member]	Dec. 31, 2011 Corporate Debt With Standard And Poor's (S&P) Rating A Or Higher [Member]	Dec. 31, 2010 Corporate Debt With Standard And Poor's (S&P) Rating A Or Higher [Member]	Dec. 31, 2011 U.S. Companies [Member] Corporate Bonds [Member]	Dec. 31, 2010 U.S. Companies [Member] Corporate Bonds [Member]	Dec. 31, 2011 International Companies [Member] Corporate Bonds [Member]	Dec. 31, 2010 International Companies [Member] Corporate Bonds [Member]	Dec. 31, 2011 Emerging Market Companies [Member] Corporate Bonds [Member]	Dec. 31, 2010 Emerging Market Companies [Member] Corporate Bonds [Member]	Dec. 31, 2011 Domestic Government Securities [Member]	Dec. 31, 2010 Domestic Government Securities [Member]	Dec. 31, 2011 Emerging Market Government Securities [Member]	Dec. 31, 2010 Emerging Market Government Securities [Member]	Dec. 31, 2011 U.S. Buyout Opportunities [Member]	Dec. 31, 2010 U.S. Buyout Opportunities [Member]	Dec. 31, 2011 European Buyout Opportunities [Member]	Dec. 31, 2010 European Buyout Opportunities [Member]	Dec. 31, 2011 Emerging Market 103-12 Investment Trust [Member]	Dec. 31, 2010 Emerging Market 103-12 Investment Trust [Member]	Dec. 31, 2011 Canadian Segregated Balanced Value [Member]	Dec. 31, 2010 Canadian Segregated Balanced Value [Member]	Dec. 31, 2011 Common/Collective Trust [Member]	Dec. 31, 2010 Common/Collective Trust [Member]	Dec. 31, 2011 Minimum [Member]	Dec. 31, 2010 Minimum [Member]	Dec. 31, 2011 Maximum [Member]	Dec. 31, 2010 Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 8,132	$ 7,773	$ 160	$ 269	$ 1,939	[1],[2]	$ 2,025	[1],[3]	$ 1,462	[1]	$ 1,557	[1]	$ 221	[1]	$ 152	[1]	$ 17	[1]	$ 37	[1]	$ 1,866	[4]	$ 1,593	[5]	$ 1,205	[6]	$ 1,194	[7]	$ 52	$ 39	$ 920	[8]	$ 795	[9]	$ 744	$ 172	[10]	$ 145	[11]	$ (74)	[12]	$ 2	$ 3	$ 3	$ 42	$ 37	$ 72	$ (11)	$ 8	$ 2	$ 4	$ 3,915	$ 4,078	$ 160	$ 269	$ 1,939	[1],[2]	$ 2,025	[1],[3]	$ 1,462	[1]	$ 1,557	[1]	$ 221	[1]	$ 152	[1]	$ 17	[1]	$ 37	[1]	$ 42	$ 37	$ 72	$ (11)	$ 8	$ 2	$ 4	$ 3,295	$ 2,897	$ 1,866	[4]	$ 1,593	[5]	$ 1,205	[6]	$ 1,194	[7]	$ 52	$ 39	$ 172	[10]	$ 145	[11]	$ (74)	[12]	$ 922	$ 798	$ 920	[8]	$ 795	[9]	$ 2	$ 3
Percentage of investments in defined benefit plan assets																																																																																																									22.00%	20.00%	10.00%	14.00%	5.00%	5.00%	6.00%	7.00%	9.00%	9.00%	7.00%	8.00%	13.00%	11.00%	23.00%	26.00%	83.00%	82.00%	17.00%	18.00%	80.00%	81.00%	18.00%	16.00%	2.00%	3.00%	89.00%	87.00%	11.00%	13.00%	92.00%	92.00%	8.00%	8.00%	71.00%	64.00%	16.00%	19.00%	13.00%	17.00%
Estimated year of liquidation of underlying assets																																																																																																																																																	1	1	10	10
Defined benefit plan future funding commitments	335	389
Master trust future funding commitments period, years	10	10
Notional value interest rate swap agreements		760
Notional amount of interest rate fair value		$ 75
Percentage of interest rate swap agreements		99.00%

[1] There are no significant concentration of holdings by company or industry.

[2] Holdings are diversified as follows: 22 percent United Kingdom, 10 percent Japan, 9 percent France, 7 percent Switzerland, 6 percent Germany, 5 percent Netherlanpercent in any one country. ds, 5 percent Republic of Korea, 13 percent emerging markets and the remaining 23 percent with no concentration greater than 5 percent in any one country.

[3] Holdings are diversified as follows: 20 percent United Kingdom, 14 percent Japan, 9 percent France, 8 percent Switzerland, 7 percent Germany, 5 percent Netherlands, 11 percent emerging markets and the remaining 26 percent with no concentration greater than 5 percent in any one country.

[4] Includes approximately 83 percent investments in corporate debt with a Standard and Poor's (S&P) rating lower than A and 17 percent investments in corporate debt with an S&P rating A or higher. Holdings include 80 percent U.S. companies, 18 percent international companies and 2 percent emerging market companies.

[5] Includes approximately 82 percent investments in corporate debt with a Standard and Poor's (S&P) rating lower than A and 18 percent investments in corporate debt with an S&P rating A or higher. Holdings include 81 percent U.S. companies, 16 percent international companies and 3 percent emerging market companies.

[6] Includes approximately 89 percent investments in domestic government securities and 11 percent in emerging market government securities. There are no significant foreign currency risks within this classification.

[7] Includes approximately 87 percent investments in domestic government securities and 13 percent in emerging market government securities. There are no significant foreign currency risks within this classification.

[8] Includes limited partnerships that invest primarily in U.S. (92%) and European (8%) buyout opportunities of a range of privately held companies. The Master Trust does not have the right to redeem its limited partnership investment at its net asset value. Instead, the Master Trust receives distributions as the underlying assets are liquidated. It is estimated that the underlying assets of these funds will be gradually liquidated over the next 1 to 10 years. Additionally, the Master Trust has future funding commitments of approximately $335 million over the next 10 years.

[9] Includes limited partnerships that invest primarily in U.S. (92%) and European (8%) buyout opportunities of a range of privately held companies. The Master Trust does not have the right to redeem its limited partnership investment at its net asset value. Instead, the Master Trust receives distributions as the underlying assets are liquidated. It is estimated that the underlying assets of these funds will be gradually liquidated over the next 1 to 10 years. Additionally, the Master Trust has future funding commitments of approximately $389 million over the next 10 years.

[10] Investment includes 71% in an emerging market 103-12 investment trust with investments in emerging country equity securities, 16% in Canadian segregated balanced value, income growth and diversified pooled funds and 13% in a common/collective trust investing in securities of smaller companies located outside the U.S., including developing markets. Requests for withdrawals must meet specific requirements with advance notice of redemption preferred.

[11] Investment includes 64% in an emerging market 103-12 investment trust with investments in emerging country equity securities, 19% in Canadian segregated balanced value, income growth and diversified pooled funds and 17% in a common/collective trust investing in securities of smaller companies located outside the U.S., including developing markets. Requests for withdrawals must meet specific requirements with advance notice of redemption preferred.

[12] Includes four interest rate swap agreements with notional value of $760 million and fair value of $75 million representing 99% of the balance.