Employee Benefits Schedule of Fair Value of U.K. Plan Assets (Details) (U.K. [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	$ 5,398		$ 4,860		$ 4,245
Fair Value [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	5,398		4,860
Fair Value [Member] | Cash and cash equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	555		298
Fair Value [Member] | Pooled funds - Global [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	668	[1]	967	[1]
Fair Value [Member] | Pooled funds - Europe [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	155	[1]	319	[1]
Fair Value [Member] | Equity securities - global [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	171	[2]	137	[2]
Fair Value [Member] | Derivatives [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	31	[2]	103	[2]
Fair Value [Member] | Pooled funds - Fixed income securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	500	[1]	501	[1]
Fair Value [Member] | Fixed income securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	2,043	[3]	1,234	[3]
Fair Value [Member] | Annuities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	564		568
Fair Value [Member] | Derivatives [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	142	[3]	217	[3]
Fair Value [Member] | Pooled funds - Real estate [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	23	[1],[4]	70	[1],[4]
Fair Value [Member] | Alternative investments [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	546	[1],[5]	446	[1],[5]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	2,769		1,669
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash and cash equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	555		298
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pooled funds - Global [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total		[1]	0	[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pooled funds - Europe [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[1]	0	[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity securities - global [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	171	[2]	137	[2]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Derivatives [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[2]	0	[2]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pooled funds - Fixed income securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[1]	0	[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed income securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	2,043	[3]	1,234	[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Annuities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Derivatives [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[3]	0	[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pooled funds - Real estate [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[1],[4]	0	[1],[4]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Alternative investments [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[1],[5]	0	[1],[5]
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	1,496		2,107
Significant Other Observable Inputs (Level 2) [Member] | Cash and cash equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0		0
Significant Other Observable Inputs (Level 2) [Member] | Pooled funds - Global [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	668	[1]	967	[1]
Significant Other Observable Inputs (Level 2) [Member] | Pooled funds - Europe [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	155	[1]	319	[1]
Significant Other Observable Inputs (Level 2) [Member] | Equity securities - global [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[2]	0	[2]
Significant Other Observable Inputs (Level 2) [Member] | Derivatives [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	31	[2]	103	[2]
Significant Other Observable Inputs (Level 2) [Member] | Pooled funds - Fixed income securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	500	[1]	501	[1]
Significant Other Observable Inputs (Level 2) [Member] | Fixed income securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[3]	0	[3]
Significant Other Observable Inputs (Level 2) [Member] | Annuities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0		0
Significant Other Observable Inputs (Level 2) [Member] | Derivatives [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	142	[3]	217	[3]
Significant Other Observable Inputs (Level 2) [Member] | Pooled funds - Real estate [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[1],[4]	0	[1],[4]
Significant Other Observable Inputs (Level 2) [Member] | Alternative investments [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[1],[5]	0	[1],[5]
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	1,133		1,084		851
Significant Unobservable Inputs (Level 3) [Member] | Cash and cash equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0		0
Significant Unobservable Inputs (Level 3) [Member] | Pooled funds - Global [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[1]	0	[1]
Significant Unobservable Inputs (Level 3) [Member] | Pooled funds - Europe [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[1]	0	[1]
Significant Unobservable Inputs (Level 3) [Member] | Equity securities - global [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[2]	0	[2]
Significant Unobservable Inputs (Level 3) [Member] | Derivatives [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[2]	0	[2]
Significant Unobservable Inputs (Level 3) [Member] | Pooled funds - Fixed income securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[1]	0	[1]
Significant Unobservable Inputs (Level 3) [Member] | Fixed income securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[3]	0	[3]
Significant Unobservable Inputs (Level 3) [Member] | Annuities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	564		568		419
Significant Unobservable Inputs (Level 3) [Member] | Derivatives [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	0	[3]	0	[3]
Significant Unobservable Inputs (Level 3) [Member] | Pooled funds - Real estate [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	23	[1],[4]	70	[1],[4]	97
Significant Unobservable Inputs (Level 3) [Member] | Alternative investments [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total	$ 546	[1],[5]	$ 446	[1],[5]	$ 335

[1] Consists of various equity, fixed income, commodity, and real estate mutual fund type investment vehicles.

[2] Consists of equity securities and equity derivatives.

[3] Consists of corporate and government bonds and fixed income derivatives.

[4] Consists of property funds and trusts holding direct real estate investments.

[5] Consists of limited partnerships, private equity and hedge funds.