The following is a reconciliation of the beginning and ending balance of pension plan assets that are measured at fair value using significant unobservable inputs:
| (dollars in millions) | ||||||||||||||||||||
| Corporate Bonds  | 
 Real Estate  | 
 Private Equity  | 
 Hedge Funds  | 
 Total | ||||||||||||||||
| 
  Balance at January 1, 2012  | 
 $ | 189 | $ | 2,158 | $ | 6,055 | $ | 662 | $ | 9,064 | ||||||||||
| 
  Actual gain on plan assets  | 
 12 | 84 | 146 | 43 | 285 | |||||||||||||||
| 
  Purchases and sales  | 
 (14 | ) | (224 | ) | (1,162 | ) | (147 | ) | (1,547 | ) | ||||||||||
| 
  Transfers in  | 
 9 | – | – | – | 9 | |||||||||||||||
| 
  
  | 
 
  
  | 
 |||||||||||||||||||
| 
  Balance at December 31, 2012  | 
 $ | 196 | $ | 2,018 | $ | 5,039 | $ | 558 | $ | 7,811 | ||||||||||
| 
  Actual gain on plan assets  | 
 12 | 81 | 674 | 84 | 851 | |||||||||||||||
| 
  Purchases and sales  | 
 (13 | ) | (315 | ) | (1,732 | ) | (124 | ) | (2,184 | ) | ||||||||||
| 
  Transfers in (out)  | 
 (33 | ) | – | (39 | ) | 678 | 606 | |||||||||||||
| 
  
  | 
 
  
  | 
 |||||||||||||||||||
| 
  Balance at December 31, 2013  | 
 $ | 162 | $ | 1,784 | $ | 3,942 | $ | 1,196 | $ | 7,084 | ||||||||||
| 
  
  | 
 
  
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