The carrying value of trade and other receivables was distributed as follows.
December 31,
SEK in millions

20072006
Accounts receivable



Invoiced receivables

1,8091,715
Allowance for doubtful receivables

-209-181
Total accounts receivable at amortized cost

1,6001,534
Currency swaps and forward exchange contracts held-for-trading

14146
Receivables from associated companies at amortized cost

4154
Loans and receivables at amortized cost

145588
Subtotal (see Categories - Note 22 and Credit risk - Note 23)

1,8902,322
Receivables from subsidiaries

34,68829,859
of which cash-pool balances

26,33922,917
of which trade and other receivables

8,3496,143
of which accrued income and deferred expenses

-799
Other current receivables

453306
Deferred expenses

145253
Total trade and other receivables

37,17632,740
of which interest-bearing

26,63523,323
of which non-interest-bearing

10,5419,417
For Accounts receivable and Loans and receivables, the carrying values equal fair value as the impact of discounting is insignificant. For more information on financial instruments by category and exposed to credit risk, see Note 22 "Financial Assets and Liabilities by Category" and section "Credit risk management" in Note 23 "Financial Risk Management," respectively. Conventional commercial terms apply for receivables from subsidiaries.
Total bad debt expenses were SEK 23 million in 2007 and SEK 70 million in 2006, while there was no recovered accounts receivable in these years. The allowance for doubtful accounts receivable changed as follows.
December 31,
SEK in millions

20072006
Opening balance

181120
Provisions for receivables impaired

7268
Unused amounts reversed

-44-7
Closing balance

209181
The accounts receivable balance includes receivables which are past due as of the balance sheet date, but not provided for as there has not been a significant change in credit quality and the amounts are still considered re-coverable. TeliaSonera AB does not hold any significant collateral over these balances. As of December 31, 2007, ageing of past due but not impaired accounts receivable was as follows.
December 31,
SEK in millions

2007
Less than 30 days

829
30 - 180 days

51
More than 180 days

10
Total past due but not impaired accounts receivable

890
See also "Notes to Consolidated Financial Statements" (section "Credit risk management" in Note 28) for information on mitigation of credit risks related to accounts receivable.