XML 32 R29.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Pension And Other Postretirement Benefits (Tables) | 6 Months Ended
--- | ---
Jun. 30, 2012
Schedule Of Components Of Net Periodic Benefit Cost | M. Pension and Other Postretirement Benefits – The components of net periodic benefit cost were as follows:
|  | Second quarter ended June 30, |  |  | Six months ended June 30, |
Pension benefits |  | 2012 |  |  | 2011 |  |  | 2012 |  |  | 2011 |
Service cost |  | $ | 46 |  |  | $ | 41 |  |  | $ | 93 |  |  | $ | 82 |
Interest cost |  |  | 160 |  |  |  | 171 |  |  |  | 320 |  |  |  | 340 |
Expected return on plan assets |  |  | (201 | ) |  |  | (202 | ) |  |  | (403 | ) |  |  | (403 | )
Amortization of prior service cost |  |  | 4 |  |  |  | 4 |  |  |  | 9 |  |  |  | 9 |
Recognized net actuarial loss |  |  | 95 |  |  |  | 62 |  |  |  | 191 |  |  |  | 124 |
Net periodic benefit cost |  | $ | 104 |  |  | $ | 76 |  |  | $ | 210 |  |  | $ | 152 |
|  | Second quarter ended June 30, |  |  | Six months ended June 30, |
Other postretirement benefits |  | 2012 |  |  | 2011 |  |  | 2012 |  |  | 2011 |
Service cost |  | $ | 3 |  |  | $ | 4 |  |  | $ | 7 |  |  | $ | 8 |
Interest cost |  |  | 33 |  |  |  | 39 |  |  |  | 66 |  |  |  | 79 |
Expected return on plan assets |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (1 | )
Amortization of prior service benefit |  |  | (4 | ) |  |  | (4 | ) |  |  | (8 | ) |  |  | (8 | )
Recognized net actuarial loss |  |  | 6 |  |  |  | 6 |  |  |  | 12 |  |  |  | 13 |
Net periodic benefit cost |  | $ | 38 |  |  | $ | 45 |  |  | $ | 77 |  |  | $ | 91 |

X
- Definition Schedule Of Components of Net Periodic Benefit Cost [Text Block] + References No definition available. + Details
Name: | aa_ScheduleOfComponentsOfNetPeriodicBenefitCostTextBlock
Namespace Prefix: | aa_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration