Retirement Plans and Other Retiree Benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Percentage Of Fixed Income Portfolio Invested In Us Treasury Or Agency Securities	75.00%		75.00%
United States Pension Benefits [Member]
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Real estate and alternative investments (in hundredths)	8.00%
Total (in hundredths)	100.00%
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	$ 1,597		$ 1,426		$ 1,377
Percentage of fixed income portfolio invested in U.S. treasury or agency securities (in hundredths)	4		3
Defined Benefit Plan Percentage Of Equity Securities Invested In Employer Securities	11.00%		11.00%
United States Pension Benefits [Member] | Equity Securities [Member]
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Equity securities (in hundredths)	52.00%
United States Pension Benefits [Member] | Cash & cash equivalents [Member] | Level 1 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	45		67
United States Pension Benefits [Member] | U.S. common stocks [Member] | Level 1 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	258		209
United States Pension Benefits [Member] | International common stocks [Member] | Level 1 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	93		47
United States Pension Benefits [Member] | Fixed income securities [Member]
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Equity securities (in hundredths)	40.00%
United States Pension Benefits [Member] | Fixed income securities [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	142	[1]	145	[1]
United States Pension Benefits [Member] | Equity index funds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	444	[2]	405	[2]
United States Pension Benefits [Member] | Emerging market equity index funds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	65	[2]	54	[2]
United States Pension Benefits [Member] | Other common stock funds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	40	[2]	34	[2]
United States Pension Benefits [Member] | Fixed income funds: U.S. or foreign government and agency securities [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	227	[2]	268	[2]
United States Pension Benefits [Member] | Fixed income funds: investment grade corporate bonds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	26	[2]	58	[2]
United States Pension Benefits [Member] | Fixed income funds: high yield corporate bonds and other [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	185	[2]	75	[2]
United States Pension Benefits [Member] | Guaranteed investment contracts [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	2	[3]	2	[3]
United States Pension Benefits [Member] | Real estate [Member] | Level 3 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	70	[4]	62	[4]
International Pension Benefits [Member]
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Real estate and alternative investments (in hundredths)	15.00%
Total (in hundredths)	100.00%
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	486		437		434
International Pension Benefits [Member] | Equity Securities [Member]
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Equity securities (in hundredths)	43.00%
International Pension Benefits [Member] | Cash & cash equivalents [Member] | Level 1 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	9		12
International Pension Benefits [Member] | U.S. common stocks [Member] | Level 1 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	0		0
International Pension Benefits [Member] | International common stocks [Member] | Level 1 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	0		0
International Pension Benefits [Member] | Fixed income securities [Member]
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Equity securities (in hundredths)	42.00%
International Pension Benefits [Member] | Fixed income securities [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	0	[1]	0	[1]
International Pension Benefits [Member] | Equity index funds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	199	[2]	158	[2]
International Pension Benefits [Member] | Emerging market equity index funds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	12	[2]	17	[2]
International Pension Benefits [Member] | Other common stock funds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	65	[2]	28	[2]
International Pension Benefits [Member] | Fixed income funds: U.S. or foreign government and agency securities [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	59	[2]	82	[2]
International Pension Benefits [Member] | Fixed income funds: investment grade corporate bonds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	72	[2]	75	[2]
International Pension Benefits [Member] | Fixed income funds: high yield corporate bonds and other [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	1	[2]	1	[2]
International Pension Benefits [Member] | Guaranteed investment contracts [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	49	[3]	46	[3]
International Pension Benefits [Member] | Real estate [Member] | Level 3 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	20	[4]	18	[4]	16
Other Retiree Benefits [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	37		32		32
Other Retiree Benefits [Member] | Cash & cash equivalents [Member] | Level 1 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	1		2
Other Retiree Benefits [Member] | U.S. common stocks [Member] | Level 1 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	6		5
Other Retiree Benefits [Member] | International common stocks [Member] | Level 1 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	2		1
Other Retiree Benefits [Member] | Fixed income securities [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	0	[1]	0	[1]
Other Retiree Benefits [Member] | Equity index funds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	11	[2]	10	[2]
Other Retiree Benefits [Member] | Emerging market equity index funds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	2	[2]	1	[2]
Other Retiree Benefits [Member] | Other common stock funds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	1	[2]	1	[2]
Other Retiree Benefits [Member] | Fixed income funds: U.S. or foreign government and agency securities [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	6	[2]	7	[2]
Other Retiree Benefits [Member] | Fixed income funds: investment grade corporate bonds [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	1	[2]	1	[2]
Other Retiree Benefits [Member] | Fixed income funds: high yield corporate bonds and other [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	5	[2]	2	[2]
Other Retiree Benefits [Member] | Guaranteed investment contracts [Member] | Level 2 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	0	[3]	0	[3]
Other Retiree Benefits [Member] | Real estate [Member] | Level 3 [Member]
Allocation of plan assets and level of valuation input for each major asset category [Abstract]
Total investments at fair value	$ 2	[4]	$ 2	[4]

[1] The fixed income securities are traded over the counter and a small portion of the securities lack daily pricing or liquidity and as such are classified as Level 2. As of December 31, 2012 and 2011, approximately 75% of the fixed income portfolio was invested in U.S. treasury or agency securities, with the remainder invested in corporate bonds.

[2] Interests in common/collective trust funds are valued using the net asset value (NAV) per unit in each fund. The NAV is based on the value of the underlying investments owned by each trust, minus its liabilities, divided by the number of shares outstanding.

[3] The guaranteed investment contracts (GICs) represent contracts with insurance companies measured at the cash surrender value of each contract. The Level 2 valuation reflects that the cash surrender value is based principally on a referenced pool of investment funds with active redemption.

[4] Real estate is valued using the NAV per unit of funds that are invested in real property, and the real property is valued using independent market appraisals. Since the appraisals include unobservable inputs, the investments in each fund are classified as Level 3.