Pension plans (Tables)

12 Months Ended

Dec. 31, 2011

Schedule of net periodic pension expense

The components of net periodic pension expense for each of the three years ending December 31, 2011 are as follows (in millions).

	2011			2010			2009
Service cost	$	191		$	165		$	162
Interest cost		568			543			455
Expected return on plan assets		(579	)		(528	)		(417	)
Other		102			69			35
Net pension expense	$	282		$	249		$	235

Schedule of changes in projected benefit obligations

Information regarding PBOs is shown in the table that follows (in millions).

	December 31,
	2011			2010
Projected benefit obligation, beginning of year	$	10,598		$	8,136
Service cost		191			165
Interest cost		568			543
Benefits paid		(579	)		(528	)
Business acquisitions		1,017			1,986
Actuarial (gains) or losses and other		1,197			296
Projected benefit obligation, end of year	$	12,992		$	10,598

Changes in plan assets

A reconciliation of the changes in plan assets and a summary of plan assets held as of December 31, 2011 and 2010 is presented in the table that follows (in millions).

	December 31,
	2011			2010
Plan assets at beginning of year	$	8,246		$	5,926
Employer contributions		523			776
Benefits paid		(579	)		(528	)
Actual return on plan assets		361			795
Business acquisitions		632			1,342
Other		(33	)		(65	)
Plan assets at end of year	$	9,150		$	8,246

Schedule of fair value measurements by major categories of plan assets

Fair value measurements for pension assets as of December 31, 2011 and 2010 follow (in millions).

	Total Fair Value		Quoted Prices (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
December 31, 2011
Cash and equivalents	$	830	$	797	$	33	$	—
Government obligations		915		534		380		1
Investment funds		1,872		402		1,465		5
Corporate debt obligations		1,180		95		1,085		—
Equity securities		3,618		3,432		186		—
Other		735		37		314		384
	$	9,150	$	5,297	$	3,463	$	390
December 31, 2010
Cash and equivalents	$	474	$	423	$	51	$	—
Government obligations		895		609		285		1
Investment funds		2,020		597		1,423		—
Corporate debt obligations		1,015		147		868		—
Equity securities		3,069		3,069		—		—
Other		773		54		349		370
	$	8,246	$	4,899	$	2,976	$	371

Schedule of net funded status of pension plans

The net funded status of the defined benefit pension plans is summarized in the table that follows (in millions).

	December 31,
	2011			2010
Amounts recognized in the Consolidated Balance Sheets:
Accounts payable, accruals and other liabilities	$	3,900		$	2,425
Other assets		(58	)		(73	)
	$	3,842		$	2,352

Schedule of pension plan amounts recognized In accumulated other comprehensive income

A reconciliation of amounts included in accumulated other comprehensive income (“AOCI”) related to defined benefit pension plans for each of the two years ending December 31, 2011 follows (in millions). We estimate that $177 million of the balance in AOCI at December 31, 2011 will be included in pension expense in 2012.

	2011			2010
Accumulated other comprehensive income (loss), beginning of year	$	(1,395	)	$	(1,368	)
Amount included in net periodic pension expense		76			53
Gains (losses) current period and other		(1,202	)		(80	)
Accumulated other comprehensive income (loss), end of year	$	(2,521	)	$	(1,395	)

Weighted Average Interest Rate Assumptions

Weighted average interest rate assumptions used in determining projected benefit obligations and net periodic pension expense were as follows.

	2011			2010
Applicable to pension benefit obligations:
Discount rate		4.6	%		5.4	%
Expected long-term rate of return on plan assets		6.9			7.1
Rate of compensation increase		3.7			3.7
Discount rate applicable to pension expense		5.3			5.8