Retirement Plans and Other Post-Retirement Benefits

3 Months Ended

Mar. 31, 2017

Compensation And Retirement Disclosure [Abstract]

Retirement Plans and Other Post-Retirement Benefits

7. RETIREMENT PLANS AND OTHER POST-RETIREMENT BENEFITS

The following tables provide information with respect to the net periodic costs of our pension and post-retirement medical benefit plans.

	Three months ended March 31
In millions	2017			2016
Pension Benefits
Service cost	$	2,721		$	2,730
Interest cost		5,907			6,087
Expected return on plan assets		(10,831	)		(11,386	)
Amortization of prior service    cost		704			674
Amortization of unrecognized    loss		2,822			3,054
Total net periodic benefit cost	$	1,323		$	1,159
Other Benefits
Service cost	$	295		$	323
Interest cost		485			540
Amortization of prior    service credit		(45	)		(45	)
Amortization of    actuarial gain		(143	)		(51	)
Total net periodic    benefit cost	$	592		$	767