Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2012

Fair Value Disclosures [Abstract]

Assets and Liabilities Reported at Fair Value on a Recurring Basis

Assets and liabilities reported at fair value on a recurring basis:

		December 31, 2012
(Millions)		Level 1		Level 2		Level 3		Total
Short-term investments:
	Commercial paper and certificates of deposit	$	—	$	455	$	—	$	455
Other current assets:
	Marketable equity securities	5		—		—		5
	Foreign currency contracts(1)	—		3		—		3
	Equity forward arrangement(1)	—		130		—		130
Investments:
	Marketable equity securities	60		—		—		60
Accounts payable and accrued liabilities:
	Foreign currency contracts(1)	—		1		—		1
Other liabilities:
	Cross currency swaps(1)	—		95		—		95

(1) This entire balance is designated as a hedging instrument under GAAP.

		December 31, 2011
(Millions)		Level 1		Level 2		Level 3		Total
Short-term investments:
	Commercial paper and restricted cash	$	—	$	21	$	—	$	21
	Marketable equity securities	4		—		—		4
Other current assets:
	Foreign currency contracts(1)	—		1		—		1
	Interest rate swaps(1)	—		1		—		1
	Equity forward arrangement(1)	—		56		—		56
Investments:
	Marketable equity securities	56		—		—		56
Other assets:
	Interest rate swaps(1)	—		25		—		25
Accounts payable and accrued liabilities:
	Foreign currency contracts(1)	—		6		—		6
	Forward starting swaps(1)	—		92		—		92
	Natural gas swap contracts(1)	—		9		—		9
Other liabilities:
	Cross currency swaps(1)	—		120		—		120
	Foreign currency contracts(1)	—		1		—		1

(1) This entire balance is designated as a hedging instrument under GAAP.