XML 42 R27.htm IDEA: XBRL DOCUMENT
v3.19.1

FINANCIAL INSTRUMENTS, OFF-BALANCE SHEET RISKS AND CONTINGENCIES (Additional Information) (Details) - USD ($) | Mar. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Carrying Amounts and Fair Values of Financial Instruments or Liabilities [Line Items] |  |
Cash investments in money market funds |  | $ 33,700,000
Deposits in domestic and foreign financial institutions | $ 272,398,311 | $ 326,091,174

X
- Definition Carrying Amounts and Fair Values of Financial Instruments or Liabilities [Line Items] + References No definition available. + Details
Name: | ung_CarryingAmountsAndFairValuesOfFinancialInstrumentsOrLiabilitiesLineItems
Namespace Prefix: | ung_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_Deposits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of deposits in accounts that offer many of the same services as checking accounts although transactions may be somewhat more limited, share some of the characteristics of a money market fund and are insured by the Federal government, also known as money market accounts. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_DepositsMoneyMarketDeposits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant