FASB ASC 17-3 Accounting for Changing Prices
The FASB ASC indicates that a business entity that prepares its financial statements in US dollars and in accordance with US GAAP is encouraged, but not required, to disclose supplementary information on the effects of changing prices.
It also describes the information that should be disclosed if such supplemental information is provided. Find, cite, and copy the FASB ASC paragraphs that discuss this issue.