CONSOLIDATED STATEMENT OF CHANGES IN MEMBER'S INTEREST (Parenthetical) $ in Millions	6 Months Ended
Jun. 30, 2019 USD ($)
IBM
Non-cash equity contribution received	$ 64

The amount of a noncash equity contribution received by the reporting entity.

No definition available.

Name:	ibmc_NoncashEquityContributionReceived
Namespace Prefix:	ibmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration