Employee Retirement Benefits (Fair Value of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	$ 619	$ 563	$ 498
U.S. Plan | Short-term Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	13	13
U.S. Plan | US Large Cap Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	171	160
U.S. Plan | US Mid Cap Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	50	46
U.S. Plan | US Small Cap Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	38	36
U.S. Plan | International Larg Cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	99	101
U.S. Plan | International Emerging Markets
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	29	18
U.S. Plan | Asset-backed Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	4	0
U.S. Plan | US Treasuries
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	63	60
U.S. Plan | Corporate Bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	123	106
U.S. Plan | Government Bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	10	6
U.S. Plan | Municipal Bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	10	11
U.S. Plan | Real Estate Bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	9	6
U.K. Pension Plan | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	130	128
U.K. Pension Plan | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	71	67
U.K. Pension Plan | Diversified Growth Funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	74	74
U.K. Pension Plan | Diversified Growth Funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	0	0
U.K. Pension Plan | U.K. Equities | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	25	24
U.K. Pension Plan | U.K. Equities | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	0	0
U.K. Pension Plan | Overseas Equities | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	31	30
U.K. Pension Plan | Overseas Equities | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets		0
U.K. Pension Plan | Foreign Overseas Corporate Bond Securities | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	0	0
U.K. Pension Plan | Foreign Overseas Corporate Bond Securities | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	21	20
U.K. Pension Plan | Index-Linked Gilts-Stocks | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	0	0
U.K. Pension Plan | Index-Linked Gilts-Stocks | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	50	$ 47
U.K. Pension Plan | U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	$ 201