Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2014

Compensation and Retirement Disclosure [Abstract]

Net Pension Cost and Amount Recognized in OCI for All Funded and Unfunded Plans

The components of net pension cost and the amount recognized in OCI for all funded and unfunded plans are as follows:

Year ended December 31, in millions	2014			2013			2012
Interest cost on PBO	$	46		$	42		$	47
Expected return on plan assets		(66	)		(67	)		(70	)
Amortization of losses		16			19			16
Settlement loss		23			27			—
Net pension cost (benefit)	$	19		$	21		$	(7	)
Other changes in plan assets and benefit obligations recognized in OCI:
Net (gain) loss	$	97		$	(106	)	$	63
Amortization of losses		(39	)		(46	)		(16	)
Total recognized in comprehensive income	$	58		$	(152	)	$	47
Total recognized in net pension cost and comprehensive income	$	77		$	(131	)	$	40

Changes in PBO Related to Pension Plans

The following table summarizes changes in the PBO related to our pension plans.

Year ended December 31, in millions	2014			2013
PBO at beginning of year	$	1,156		$	1,277
Interest cost		46			42
Actuarial losses (gains)		97			(54	)
Benefit payments		(93	)		(109	)
PBO at end of year	$	1,206		$	1,156

Changes in FVA

The following table summarizes changes in the FVA.

Year ended December 31, in millions	2014			2013
FVA at beginning of year	$	970		$	942
Actual return on plan assets		66			119
Employer contributions		14			18
Benefit payments		(93	)		(109	)
FVA at end of year	$	957		$	970

Funded Status of Pension Plans Recognized in Balance Sheets

The following table summarizes the funded status of the pension plans, which equals the amounts recognized in the balance sheets at December 31, 2014, and December 31, 2013.

December 31, in millions	2014			2013
Funded status (a)	$	(249	)	$	(186	)
Net prepaid pension cost recognized consists of:
Current liabilities	$	(14	)	$	(14	)
Noncurrent liabilities		(235	)		(172	)
Net prepaid pension cost recognized (b)	$	(249	)	$	(186	)

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

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

Plans ABO in Excess of Plan Assets

The ABO for all of our pension plans was $1.2 billion at December 31, 2014, and December 31, 2013. As indicated in the table below, collectively our plans had an ABO in excess of plan assets as follows:

December 31,
in millions	2014		2013
PBO	$	1,206	$	1,156
ABO		1,206		1,156
Fair value of plan assets		957		970

Weighted-Average Rates to Determine Actuarial Present Value of Benefit Obligations

To determine the actuarial present value of benefit obligations, we assumed the following weighted-average rates.

December 31,	2014			2013
Discount rate		3.50	%		4.25	%
Compensation increase rate		N/A			N/A

Weighted-Average Rates to Determine Net Pension Cost

To determine net pension cost, we assumed the following weighted-average rates.

Year ended December 31,	2014			2013			2012
Discount rate		4.25	%		3.25	%		4.00	%
Compensation increase rate		N/A			N/A			N/A
Expected return on plan assets		7.25			7.25			7.25

Asset Target Allocations Prescribed by Pension Funds' Investment Policies

The following table shows the asset target allocations prescribed by the pension funds’ investment policies based on the plan’s funded status at December 31, 2014.

Asset Class	Target   Allocation   2014
Equity securities:
U.S.		20	%
International		16
Fixed income securities		40
Convertible securities		5
Real assets		13
Other assets		6
Total		100	%

Fair Values of Pension Plan Assets by Asset Category

The following tables show the fair values of our pension plan assets by asset class at December 31, 2014, and December 31, 2013.

December 31, 2014
in millions	Level 1		Level 2		Level 3		Total
ASSET CLASS
Equity securities:
U.S.	$	161		—		—	$	161
International		10		—		—		10
Debt securities:
Corporate bonds — U.S.		—	$	43		—		43
Corporate bonds — International		—		7		—		7
Government and agency bonds — U.S.		—		253		—		253
Government bonds — International		—		1		—		1
State and municipal bonds		—		1		—		1
Mutual funds:
U.S. equity		18		—		—		18
International equity		28		—		—		28
Fixed income — U.S.		2		—		—		2
Fixed income — International		2		—		—		2
Collective investment funds:
U.S. equity		—		28		—		28
International equity		—		118		—		118
Convertible securities		—		45		—		45
Fixed income securities		—		16		—		16
Short-term investments		—		31		—		31
Real assets		—		113		—		113
Insurance investment contracts and pooled separate accounts		—		—	$	14		14
Other assets		—		—		66		66
Total net assets at fair value	$	221	$	656	$	80	$	957

December 31, 2013
in millions	Level 1		Level 2		Level 3		Total
ASSET CLASS
Equity securities:
U.S.	$	216		—		—	$	216
International		24		—		—		24
Debt securities:
Corporate bonds — U.S.		—	$	74		—		74
Corporate bonds — International		—		11		—		11
Government and agency bonds — U.S.		—		73		—		73
Government bonds — International		—		1		—		1
State and municipal bonds		—		3		—		3
Mutual funds:
U.S. equity		11		—		—		11
International equity		34		—		—		34
Fixed Income — U.S.		3		—		—		3
Fixed Income — International		2		—		—		2
Collective investment funds:
U.S. equity		—		31		—		31
International equity		—		151		—		151
Convertible securities		—		54		—		54
Fixed income securities		—		7		—		7
Short-term investments		—		44		—		44
Emerging markets		—		44		—		44
Real assets		—		112		—		112
Insurance investment contracts and pooled separate accounts		—		—	$	13		13
Other assets		—		—		62		62
Total net assets at fair value	$	290	$	605	$	75	$	970

Changes in Fair Values of Level 3 Plan Assets

The following table shows the changes in the fair values of our Level 3 plan assets for the years ended December 31, 2014, and December 31, 2013.

in millions	Insurance Investment Contracts and Pooled Separate Accounts		Other Assets		Total
Balance at December 31, 2012	$	12	$	56	$	68
Actual return on plan assets:
Relating to assets held at reporting date		1		6		7
Balance at December 31, 2013	$	13	$	62	$	75
Actual return on plan assets:
Relating to assets held at reporting date		1		4		5
Balance at December 31, 2014	$	14	$	66	$	80

Pre-tax AOCI Not Yet Recognized as Net Postretirement Benefit Cost

The components of pre-tax AOCI not yet recognized as net postretirement benefit cost are shown below.

December 31,
in millions	2014			2013
Net unrecognized losses (gains)	$	2		$	(12)
Net unrecognized prior service credit		(5	)		(5)
Total unrecognized AOCI	$	(3	)	$	(17)

Net Postretirement Benefit Cost and Amount Recognized in OCI for All Funded and Unfunded Plans

The components of net postretirement benefit cost and the amount recognized in OCI for all funded and unfunded plans are as follows:

December 31,
in millions	2014			2013			2012
Service cost of benefits earned	$	1		$	1		$	1
Interest cost on APBO		3			3			3
Expected return on plan assets		(3	)		(3	)		(3)
Amortization of prior service credit		(1	)		(1	)		(1)
Amortization of losses		(1	)		—			—
Net postretirement benefit cost	$	(1	)		—			—
Other changes in plan assets and benefit obligations recognized in OCI:
Net (gain) loss	$	13		$	(17	)	$	(3)
Amortization of prior service credit		1			1			1
Amortization of losses		1			—			—
Total recognized in comprehensive income	$	15		$	(16	)	$	(2)
Total recognized in net postretirement benefit cost and comprehensive income	$	14		$	(16	)	$	(2)

Changes in APBO

The following table summarizes changes in the APBO.

Year ended December 31,
in millions	2014		2013
APBO at beginning of year	$	65	$	74
Service cost		1		1
Interest cost		3		3
Plan participants’ contributions		2		1
Actuarial losses (gains)		15		(6)
Benefit payments		(7)		(8)
APBO at end of year	$	79	$	65

Change in FVA (Other Post Retirement Benefit Plan Assets)

The following table summarizes changes in FVA.

Year ended December 31,
in millions	2014		2013
FVA at beginning of year	$	57	$	51
Employer contributions		(1)		—
Plan participants’ contributions		2		1
Benefit payments		(7)		(8)
Actual return on plan assets		5		13
FVA at end of year	$	56	$	57

Funded Status of Postretirement Plans Recognized in Balance Sheets

The following table summarizes the funded status of the postretirement plans, which corresponds to the amounts recognized in the balance sheets at December 31, 2014, and December 31, 2013.

December 31,
in millions	2014			2013
Funded status (a)	$	(23	)	$	(8	)
Accrued postretirement benefit cost recognized (b)		(23	)		(8	)

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

(b) Consists entirely of noncurrent liabilities.

Weighted-Average Rates to Determine Net Postretirement Benefit Cost

To determine net postretirement benefit cost, we assumed the following weighted-average rates.

Year ended December 31,	2014			2013			2012
Discount rate		4.50	%		3.50	%		4.00	%
Expected return on plan assets		5.25			5.25			5.58

Asset Target Allocations Prescribed by Trusts' Investment Policies

The following table shows the asset target allocations prescribed by the trust’s investment policy.

Asset Class	Target   Allocation   2014
Equity securities		80	%
Fixed income securities		10
Convertible securities		5
Cash equivalents		5
Total		100	%

Fair Values of Postretirement Plan Assets by Asset Category

The following tables show the fair values of our postretirement plan assets by asset class at December 31, 2014, and December 31, 2013.

December 31, 2014
in millions	Level 1		Level 2		Level 3		Total
ASSET CLASS
Mutual funds:
U.S. equity	$	18		—		—	$	18
International equity		1		—		—		1
U.S. fixed income		4		—		—		4
International fixed income		1		—		—		1
Common investment funds:
U.S. equity		—	$	21		—		21
International equity		—		7		—		7
Convertible securities		—		3		—		3
Short-term investments		—		1		—		1
Total net assets at fair value	$	24	$	32		—	$	56

December 31, 2013
in millions	Level 1		Level 2		Level 3		Total
ASSET CLASS
Mutual funds — U.S. equity	$	6		—		—	$	6
Common investment funds:
U.S. equity		—	$	29		—		29
International equity		—		9		—		9
Convertible securities		—		3		—		3
Fixed income		—		2		—		2
Short-term investments		—		8		—		8
Total net assets at fair value	$	6	$	51		—	$	57