v3.6.0.2
Reconciliation of Benefit Obligations, Plan Assets, and Unfunded or Funded Status (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Change in plan assets      
Fair value of plan assets at beginning of year $ 33,909    
Fair value of plan assets at end of year 33,204 $ 33,909  
Qualified defined benefit pension plans      
Change in benefit obligation      
Benefit obligations at beginning of year 43,702 45,882  
Service cost [1] 827 836 $ 841
Interest cost [1] 1,861 1,791 1,912
Benefits paid (2,172) (2,055)  
Actuarial losses (gains) 1,402 (1,988)  
New longevity assumptions [2] (687) (834)  
Plan amendments and acquisitions [3] 110 31  
Service cost related to discontinued operations 21 39  
Benefit obligations at end of year 45,064 43,702 45,882
Change in plan assets      
Fair value of plan assets at beginning of year 32,096 34,673  
Actual return on plan assets 1,470 (527)  
Benefits paid (2,172) (2,055)  
Company contributions 23 5  
Fair value of plan assets at end of year 31,417 32,096 34,673
Unfunded status of the plans (13,647) (11,606)  
Retiree medical and life insurance plans      
Change in benefit obligation      
Benefit obligations at beginning of year 2,883 3,034  
Service cost 24 21 22
Interest cost 119 110 123
Benefits paid (222) (307)  
Actuarial losses (gains) (135) (170)  
New longevity assumptions [2] (53) (77)  
Plan amendments and acquisitions [3] (32) 157  
Medicare Part D subsidy 4 14  
Participants' contributions 61 101  
Benefit obligations at end of year 2,649 2,883 3,034
Change in plan assets      
Fair value of plan assets at beginning of year 1,813 1,932  
Actual return on plan assets 95 (27)  
Benefits paid (222) (307)  
Company contributions 36 100  
Medicare Part D subsidy 4 14  
Participants' contributions 61 101  
Fair value of plan assets at end of year 1,787 1,813 $ 1,932
Unfunded status of the plans $ (862) $ (1,070)  
[1] Total net periodic benefit cost associated with our qualified defined benefit plans represents pension expense calculated in accordance with GAAP (FAS pension expense). We are required to calculate pension expense in accordance with both GAAP and CAS rules, each of which results in a different calculated amount of pension expense. The CAS pension cost is recovered through the pricing of our products and services on U.S. Government contracts and, therefore, is recognized in net sales and cost of sales for products and services. We include the difference between FAS pension expense and CAS pension cost, referred to as the FAS/CAS pension adjustment, as a component of other unallocated, net on our consolidated statements of earnings. The FAS/CAS pension adjustment, which was $902 million in 2016, $400 million in 2015, and $317 million in 2014, effectively adjusts the amount of CAS pension cost in the business segment operating profit so that pension expense recorded on our consolidated statements of earnings is equal to FAS pension expense. FAS pension expense and CAS pension costs reflect the reclassification for discontinued operations presentation of benefits related to former IS&GS salaried employees.
[2] We adopted new longevity assumptions originally published by the Society of Actuaries in October 2014. The Society of Actuaries refined their original publication in October 2015 and again in October 2016.
[3] Includes special termination benefits of $27 million for qualified pension and $9 million for retiree medical recognized in 2016 related to former IS&GS salaried employees. The November 2015 acquisition of Sikorsky increased our qualified defined benefit pension obligations by about $30 million.