Book value is the value of an asset, liability or equity as it appears on the balance sheet. Book value of a whole business equals the book value of its total assets minus the book value of its total liabilities.
Book value is determined in accordance with the applicable accounting framework (such as US GAAP or IFRS). It is common to find book values differing significantly from the relevant fair values. Book values are more reliable than fair values in the sense that they are calculated in accordance with accounting rules that involve significantly less management discretion. However, book values are less relevant because in many cases they are outdated and do not represent the relevant asset, liability or equity's current worth.
Carrying amount or carrying value are terms used synonymously with book value.
The sum of HP's total assets as it appears on its balance sheet as at 31 October 2012 equals $108,768 million. The relevant balances of total liabilities and total equity as at 31 October 2012 are $85,935 million and $22,833 million.
Total assets include assets that are carried at their historical cost (such as property, plant and equipment, accounts receivable, etc.) plus there are assets that are carried at lower of cost or market i.e. inventories. Further, there are assets carried at their current market values (such as certain financial instruments).
When book value is referred to in the context of the whole company, it equals the book value of the company's total equity (i.e. book value of its assets minus book value of its liabilities).
Book value of HP = $108,768 million - $85,935 million = $22,833 million