Retirement Benefits (Details 11) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension Plans Defined Benefit [Member]
Assets Fair Value
Total	$ 6,722	$ 6,822
Liabilities Fair Value
Total		6,821
Pension Plans Defined Benefit [Member] | Domestic [Member]
Assets Fair Value
Total	1,688	1,778
Pension Plans Defined Benefit [Member] | International [Member]
Assets Fair Value
Total	1,527	1,720
Pension Plans Defined Benefit [Member] | U.S. Treasury, government, and agency bonds [Member]
Assets Fair Value
Total	433	304
Pension Plans Defined Benefit [Member] | Mortgage and asset backed securities [Member]
Assets Fair Value
Total	135	247
Pension Plans Defined Benefit [Member] | Corporate bonds [Member]
Assets Fair Value
Total	835	596
Pension Plans Defined Benefit [Member] | Pooled Funds [Member]
Assets Fair Value
Total	380	201
Pension Plans Defined Benefit [Member] | Cash equivalents and other [Member]
Assets Fair Value
Total	140	480
Pension Plans Defined Benefit [Member] | Real estate investments [Member]
Assets Fair Value
Total	1,002	858
Pension Plans Defined Benefit [Member] | Private equity [Member]
Assets Fair Value
Total	582	638
Pension Plans Defined Benefit [Member] | Derivatives [Member]
Liabilities Fair Value
Total		(1)
Other Postretirement Benefits [Member]
Assets Fair Value
Total	786	790
Other Postretirement Benefits [Member] | Domestic [Member]
Assets Fair Value
Total	194	221
Other Postretirement Benefits [Member] | International [Member]
Assets Fair Value
Total	84	99
Other Postretirement Benefits [Member] | U.S. Treasury, government, and agency bonds [Member]
Assets Fair Value
Total	24	15
Other Postretirement Benefits [Member] | Mortgage and asset backed securities [Member]
Assets Fair Value
Total	5	10
Other Postretirement Benefits [Member] | Corporate bonds [Member]
Assets Fair Value
Total	32	23
Other Postretirement Benefits [Member] | Pooled Funds [Member]
Assets Fair Value
Total	48	34
Other Postretirement Benefits [Member] | Cash equivalents and other [Member]
Assets Fair Value
Total	46	41
Other Postretirement Benefits [Member] | Trust owned life insurance [Member]
Assets Fair Value
Total	291	291
Other Postretirement Benefits [Member] | Real estate investments [Member]
Assets Fair Value
Total	39	33
Other Postretirement Benefits [Member] | Private equity [Member]
Assets Fair Value
Total	23	23
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member]
Assets Fair Value
Total	2,563	2,729
Liabilities Fair Value
Total		2,728
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member] | Domestic [Member]
Assets Fair Value
Total	1,155	1,266
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member] | International [Member]
Assets Fair Value
Total	1,187	1,277
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member] | U.S. Treasury, government, and agency bonds [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member] | Mortgage and asset backed securities [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member] | Corporate bonds [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member] | Pooled Funds [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member] | Cash equivalents and other [Member]
Assets Fair Value
Total	1	2
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member] | Real estate investments [Member]
Assets Fair Value
Total	220	184
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member] | Private equity [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Plans Defined Benefit [Member] | Derivatives [Member]
Liabilities Fair Value
Total		(1)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member]
Assets Fair Value
Total	210	232
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member] | Domestic [Member]
Assets Fair Value
Total	156	176
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member] | International [Member]
Assets Fair Value
Total	45	49
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member] | U.S. Treasury, government, and agency bonds [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member] | Mortgage and asset backed securities [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member] | Corporate bonds [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member] | Pooled Funds [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member] | Cash equivalents and other [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member] | Trust owned life insurance [Member]
Assets Fair Value
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member] | Real estate investments [Member]
Assets Fair Value
Total	9	7
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Postretirement Benefits [Member] | Private equity [Member]
Assets Fair Value
Total	0	0
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member]
Assets Fair Value
Total	2,792	2,778
Liabilities Fair Value
Total		2,778
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member] | Domestic [Member]
Assets Fair Value
Total	533	511
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member] | International [Member]
Assets Fair Value
Total	340	443
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member] | U.S. Treasury, government, and agency bonds [Member]
Assets Fair Value
Total	433	304
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member] | Mortgage and asset backed securities [Member]
Assets Fair Value
Total	135	247
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member] | Corporate bonds [Member]
Assets Fair Value
Total	832	594
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member] | Pooled Funds [Member]
Assets Fair Value
Total	380	201
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member] | Cash equivalents and other [Member]
Assets Fair Value
Total	139	478
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member] | Real estate investments [Member]
Assets Fair Value
Total	0	0
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member] | Private equity [Member]
Assets Fair Value
Total	0	0
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans Defined Benefit [Member] | Derivatives [Member]
Liabilities Fair Value
Total		0
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member]
Assets Fair Value
Total	523	509
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member] | Domestic [Member]
Assets Fair Value
Total	38	45
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member] | International [Member]
Assets Fair Value
Total	39	50
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member] | U.S. Treasury, government, and agency bonds [Member]
Assets Fair Value
Total	24	15
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member] | Mortgage and asset backed securities [Member]
Assets Fair Value
Total	5	10
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member] | Corporate bonds [Member]
Assets Fair Value
Total	32	23
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member] | Pooled Funds [Member]
Assets Fair Value
Total	48	34
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member] | Cash equivalents and other [Member]
Assets Fair Value
Total	46	41
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member] | Trust owned life insurance [Member]
Assets Fair Value
Total	291	291
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member] | Real estate investments [Member]
Assets Fair Value
Total	0	0
Significant Other Observable Inputs (Level 2) [Member] | Other Postretirement Benefits [Member] | Private equity [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member]
Assets Fair Value
Total	1,367	1,315
Liabilities Fair Value
Total		1,315
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member] | Domestic [Member]
Assets Fair Value
Total	0	1
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member] | International [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member] | U.S. Treasury, government, and agency bonds [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member] | Mortgage and asset backed securities [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member] | Corporate bonds [Member]
Assets Fair Value
Total	3	2
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member] | Pooled Funds [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member] | Cash equivalents and other [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member] | Real estate investments [Member]
Assets Fair Value
Total	782	674	547
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member] | Private equity [Member]
Assets Fair Value
Total	582	638	555
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans Defined Benefit [Member] | Derivatives [Member]
Liabilities Fair Value
Total		0
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member]
Assets Fair Value
Total	53	49
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member] | Domestic [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member] | International [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member] | U.S. Treasury, government, and agency bonds [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member] | Mortgage and asset backed securities [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member] | Corporate bonds [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member] | Pooled Funds [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member] | Cash equivalents and other [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member] | Trust owned life insurance [Member]
Assets Fair Value
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member] | Real estate investments [Member]
Assets Fair Value
Total	30	26	24
Significant Unobservable Inputs (Level 3) [Member] | Other Postretirement Benefits [Member] | Private equity [Member]
Assets Fair Value
Total	$ 23	$ 23	$ 24