Retirement Plans (Details 7) (Pension [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Retirement Plans [Line Items]
Fair value of plan assets	$ 3,429		$ 2,875		$ 2,505
Temporary Cash Investments [Member]
Retirement Plans [Line Items]
Fair value of plan assets	16		14
Registered Investment Companies [Member]
Retirement Plans [Line Items]
Fair value of plan assets	264		268
U.S. Government Securities [Member]
Retirement Plans [Line Items]
Fair value of plan assets	126		125
Corporate Bonds & Debentures [Member]
Retirement Plans [Line Items]
Fair value of plan assets	310		326
Corporate Stock [Member]
Retirement Plans [Line Items]
Fair value of plan assets	999		770
Venture Capital And Buyout Partnerships [Member]
Retirement Plans [Line Items]
Fair value of plan assets	213		179
Real Estate Partnerships [Member]
Retirement Plans [Line Items]
Fair value of plan assets	139		143
Common Trust And Other Funds [Member]
Retirement Plans [Line Items]
Fair value of plan assets	1,357		1,018
Other Investments [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		27
Other Assets - Pension Plan [Member]
Retirement Plans [Line Items]
Fair value of plan assets	5	[1]	5	[1]
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member]
Retirement Plans [Line Items]
Fair value of plan assets	1,010		782
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Temporary Cash Investments [Member]
Retirement Plans [Line Items]
Fair value of plan assets	16		14
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Registered Investment Companies [Member]
Retirement Plans [Line Items]
Fair value of plan assets	11		10
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. Government Securities [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Corporate Bonds & Debentures [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Corporate Stock [Member]
Retirement Plans [Line Items]
Fair value of plan assets	983		758
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Venture Capital And Buyout Partnerships [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Real Estate Partnerships [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Common Trust And Other Funds [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Other Investments [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Significant Other Observable Inputs (Level 2) [Member]
Retirement Plans [Line Items]
Fair value of plan assets	2,062		1,766
Significant Other Observable Inputs (Level 2) [Member] | Temporary Cash Investments [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Significant Other Observable Inputs (Level 2) [Member] | Registered Investment Companies [Member]
Retirement Plans [Line Items]
Fair value of plan assets	253		258
Significant Other Observable Inputs (Level 2) [Member] | U.S. Government Securities [Member]
Retirement Plans [Line Items]
Fair value of plan assets	126		125
Significant Other Observable Inputs (Level 2) [Member] | Corporate Bonds & Debentures [Member]
Retirement Plans [Line Items]
Fair value of plan assets	310		326
Significant Other Observable Inputs (Level 2) [Member] | Corporate Stock [Member]
Retirement Plans [Line Items]
Fair value of plan assets	16		12
Significant Other Observable Inputs (Level 2) [Member] | Venture Capital And Buyout Partnerships [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Significant Other Observable Inputs (Level 2) [Member] | Real Estate Partnerships [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Significant Other Observable Inputs (Level 2) [Member] | Common Trust And Other Funds [Member]
Retirement Plans [Line Items]
Fair value of plan assets	1,357		1,018
Significant Other Observable Inputs (Level 2) [Member] | Other Investments [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		27
Significant Unobservable Inputs (Level 3) [Member]
Retirement Plans [Line Items]
Fair value of plan assets	352		322		310
Significant Unobservable Inputs (Level 3) [Member] | Temporary Cash Investments [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member] | Registered Investment Companies [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member] | U.S. Government Securities [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member] | Corporate Bonds & Debentures [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member] | Corporate Stock [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member] | Venture Capital And Buyout Partnerships [Member]
Retirement Plans [Line Items]
Fair value of plan assets	213		179		184
Significant Unobservable Inputs (Level 3) [Member] | Real Estate Partnerships [Member]
Retirement Plans [Line Items]
Fair value of plan assets	139		143		126
Significant Unobservable Inputs (Level 3) [Member] | Common Trust And Other Funds [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member] | Other Investments [Member]
Retirement Plans [Line Items]
Fair value of plan assets	$ 0		$ 0

[1] Other assets include accrued receivables and pending broker settlements.