Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2011

Employee Benefits (Tables) [Abstract]

Net pension cost and the amount recognized in other comprehensive income for all funded and unfunded plans

Year ended December 31, in millions	2011			2010			2009
Service cost of benefits earned		—			—		$	50
Interest cost on PBO	$	57		$	60			58
Expected return on plan assets		(81	)		(72	)		(65	)
Amortization of prior service cost		—			—			1
Amortization of losses		11			12			42
Curtailment loss (gain)		—			—			5
Net pension cost	$	(13	)		—		$	91
Other changes in plan assets and benefit obligations recognized in other comprehensive income:
Prior service cost due to curtailment		—			—		$	(5	)
Net loss (gain)	$	120		$	54			28
Prior service cost (benefit)		—			—			(1	)
Amortization of losses		(11	)		(12	)		(42	)
Total recognized in comprehensive income	$	109		$	42		$	(20	)
Total recognized in net pension cost and comprehensive income	$	96		$	42		$	71

Changes in PBO related to pension plans

Year ended December 31, in millions	2011			2010
PBO at beginning of year	$	1,250		$	1,202
Interest cost		57			60
Actuarial losses (gains)		9			79
Benefit payments		(88	)		(91	)
PBO at end of year	$	1,228		$	1,250

Changes in the FVA

Year ended December 31, in millions	2011			2010
FVA at beginning of year	$	914		$	839
Actual return on plan assets		(29	)		96
Employer contributions		121			70
Benefit payments		(88	)		(91	)
FVA at end of year	$	918		$	914

Funded status of the pension plans recognized in the balance sheets

December 31, in millions	2011		2010
Funded status (a)	$	(310)	$	(336)
Net prepaid pension cost recognized consists of:
Current liabilities	$	(14)	$	(14)
Noncurrent liabilities		(296)		(322)
Net prepaid pension cost recognized (b)	$	(310)	$	(336)

(a) The shortage of the FVA under the PBO.

(b) Represents the accrued benefit liability of the pension plans.

Plans had an ABO in excess of plan assets

December 31,
in millions	2011		2010
PBO	$	1,228	$	1,250
ABO		1,225		1,248
Fair value of plan assets		918		914

Weighted-average rates to determine the actuarial present value of benefit obligations

December 31,	2011			2010
Discount rate		4.00	%		4.75	%
Compensation increase rate		N/A			N/A

Weighted-average rates to determine net pension cost

Year ended December 31,	2011			2010			2009
Discount rate		4.75	%		5.25	%		5.75	%
Compensation increase rate		N/A			N/A			4.00
Expected return on plan assets		7.75			8.25			8.25

Asset target allocations prescribed by the pension funds' investment policies

Asset Class	Target   Allocation   2011
Equity securities		46	%
Fixed income securities		28
Convertible securities		5
Other assets		21
Total		100	%

Fair values of pension plan assets by asset category

December 31, 2011
in millions	Level 1		Level 2		Level 3		Total
ASSET CATEGORY
Equity securities:
U.S.	$	336		—		—	$	336
International		39		—		—		39
Emerging markets		1		—		—		1
Fixed income securities:
Corporate bonds — U.S.		—	$	70		—		70
Corporate bonds — International		—		7		—		7
Government and agency bonds — U.S.		—		73		—		73
Government bonds — International		—		3		—		3
Convertible bonds — U.S.		—		1		—		1
Mutual funds:
U.S. equity		11		—		—		11
International equity		149		1		—		150
Fixed income — U.S.		4		—		—		4
Fixed income — International		2		—		—		2
Government and agency bonds — U.S.		72		—		—		72
Common trust funds:
U.S. equity		—		21		—		21
Fixed income securities		—		4		—		4
Convertible securities		—		44		—		44
Short-term investments		—		40		—		40
Emerging markets		—		24		—		24
Insurance company contracts		—		—	$	12		12
Multi-strategy investment funds		—		—		4		4
Total net assets at fair value	$	614	$	288	$	16	$	918

December 31, 2010
in millions	Level 1		Level 2		Level 3		Total
ASSET CATEGORY
Equity securities:
U.S.	$	376		—		—	$	376
International		42		—		—		42
Emerging markets		1		—		—		1
Fixed income securities:
Corporate bonds — U.S.		—	$	58		—		58
Corporate bonds — International		—		5		—		5
Government and agency bonds — U.S.		—		75		—		75
Government bonds — International		—		2		—		2
Convertible bonds — U.S.		—		2		—		2
Mutual funds:
International equity		133		—		—		133
Government and agency bonds — U.S.		53		—		—		53
Common trust funds:
U.S. equity		—		27		—		27
Fixed income securities		—		11		—		11
Convertible securities		—		45		—		45
Short-term investments		—		43		—		43
Emerging markets		—		24		—		24
Insurance company contracts		—		—	$	11		11
Multi-strategy investment funds		—		—		6		6
Total net assets at fair value	$	605	$	292	$	17	$	914

Changes in the fair values of level three plan assets

in millions	Insurance Company Contracts		Multi- Strategy Investment Funds		Total
Balance at December 31, 2009	$	11	$	26	$	37
Purchases, sales and settlements, net		—		(20)		(20)
Balance at December 31, 2010	$	11	$	6	$	17
Actual return on plan assets:
Relating to assets held at reporting date		1		3		4
Relating to assets sold during the period		—		(4)		(4)
Sales		—		(1)		(1)
Balance at December 31, 2011	$	12	$	4	$	16

Pre tax Accumulated Other Comprehensive Income not yet recognized as net postretirement benefit cost

December 31,
in millions	2011			2010
Net unrecognized losses (gains)	$	8			—
Net unrecognized prior service benefit		(8	)	$	(9)
Total unrecognized AOCI		—		$	(9)

Net postretirement benefit cost and the amount recognized in other comprehensive income for all funded and unfunded plans

December 31,
in millions	2011			2010			2009
Service cost of benefits earned	$	1		$	1		$	1
Interest cost on APBO		3			3			4
Expected return on plan assets		(3	)		(3	)		(3)
Amortization of prior service cost		(1	)		(1	)		(1)
Net postretirement benefit cost		—			—		$	1
Other changes in plan assets and benefit obligations recognized in OCI:
Net (gain) loss	$	8		$	1		$	(4)
Prior service cost (benefit)		—			—			2
Amortization of prior service cost		1			1			1
Total recognized in comprehensive income	$	9		$	2		$	(1)
Total recognized in net postretirement benefit cost and comprehensive income	$	9		$	2			—

Change in APBO

Year ended December 31,
in millions	2011		2010
APBO at beginning of year	$	75	$	72
Service cost		1		1
Interest cost		3		3
Plan participants’ contributions		5		5
Actuarial losses (gains)		3		5
Benefit payments		(8)		(11)
Medicare retiree drug subsidy		2		—
APBO at end of year	$	81	$	75

Change in FVA (Other Post Retirement Benefit Plan Assets)

Year ended December 31,
in millions	2011		2010
FVA at beginning of year	$	61	$	58
Employer contributions		1		1
Plan participants’ contributions		5		5
Benefit payments		(8)		(11)
Actual return on plan assets		(2)		8
FVA at end of year	$	57	$	61

Funded status of the postretirement plans recognized in the balance sheets

December 31,
in millions	2011			2010
Funded status (a)	$	(24	)	$	(14	)
Accrued postretirement benefit cost recognized (b)		(24	)		(14	)

(a) The shortage of the FVA under the APBO.

(b) Consists entirely of noncurrent liabilities.

Weighted-average rates to determine net postretirement benefit cost

Year ended December 31,	2011			2010			2009
Discount rate		4.75	%		5.25	%		5.75	%
Expected return on plan assets		5.45			5.46			5.48

Assumptions regarding healthcare cost trend rates

December 31,	2011			2010
Healthcare cost trend rate assumed for the next year:
Under age 65		8.50	%		8.00	%
Age 65 and over		N/A			N/A
Rate to which the cost trend rate is assumed to decline		5.00			5.00
Year that the rate reaches the ultimate trend rate		2019			2019

Asset target allocation ranges prescribed by the trusts' investment policies

Asset Class	Target Allocation             Range             2011
Equity securities		70 - 90	%
Fixed income securities		0 - 10
Convertible securities		0 - 10
Cash equivalents and other assets		10 - 30

Fair values of postretirement plan assets by asset category

December 31, 2011
in millions	Level 1		Level 2		Level 3		Total
ASSET CATEGORY
Common trust funds:
U.S. equities		—	$	36		—	$	36
International equities		—		8		—		8
Convertible securities		—		4		—		4
Short-term investments		—		8		—		8
Fixed income		—		1		—		1
Total net assets at fair value		—	$	57		—	$	57

December 31, 2010
in millions	Level 1		Level 2		Level 3		Total
ASSET CATEGORY
Common trust funds:
U.S. equities		—	$	45		—	$	45
International equities		—		9		—		9
Convertible securities		—		4		—		4
Short-term investments		—		2		—		2
Fixed income		—		1		—		1
Total net assets at fair value		—	$	61		—	$	61