Fair Value Measurement (Tables)

6 Months Ended

Jun. 30, 2011

Fair Value Measurement (Tables) [Abstract]

Assets and liabilities measured at fair value on a recurring basis

	June 30, 2011
	Quoted
	prices in
	active markets
	for		Significant other		Significant other
	identical assets		observable inputs		unobservable inputs
	Level 1		Level 2		Level 3		Total
	(millions)
Assets at fair value:
Cash and cash equivalents	$	317	$	—	$	—	$	317
Fiduciary funds—restricted (included within Fiduciary assets)		1,957		—		—		1,957
Derivative financial instruments		—		50		—		50
Total assets	$	2,274	$	50	$	—	$	2,324
Liabilities at fair value:
Derivative financial instruments	$	—	$	14	$	—	$	14
Changes in fair value of hedged debt(i)		—		16		—		16
Total liabilities	$	—	$	30	$	—	$	30

	December 31, 2010
	Level 1		Level 2		Level 3		Total
	(millions)
Assets at fair value:
Cash and cash equivalents	$	316	$	—	$	—	$	316
Fiduciary funds—restricted (included within Fiduciary assets)		1,764		—		—		1,764
Derivative financial instruments		—		47		—		47
Total assets	$	2,080	$	47	$	—	$	2,127
Liabilities at fair value:
Derivative financial instruments	$	—	$	12	$	—	$	12
Changes in fair value of hedged debt(i)		—		12		—		12
Total liabilities	$	—	$	24	$	—	$	24

Summary of the estimated fair value of the company's financial instruments held or issued to finance the company's operations

	June 30, 2011				December 31, 2010
	Carrying		Fair		Carrying		Fair
	amount		value		amount		value
	(millions)
Assets:
Cash and cash equivalents	$	317	$	317	$	316	$	316
Fiduciary funds—restricted (included within Fiduciary assets)		1,957		1,957		1,764		1,764
Derivative financial instruments		50		50		47		47
Liabilities:
Short-term debt	$	114	$	114	$	110	$	110
Long-term debt		2,307		2,436		2,157		2,450
Derivative financial instruments		14		14		12		12