Significant Accounting Policies (Narrative) (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Significant Accounting Policies [Abstract]
Percentage of platinum held by the Zurich Sub-Custodian		5.00%		5.00%
Basket of shares				50,000
Fair value transfers		$ 0		$ 0		$ 0
Platinum receivable		0		0
Platinum payable		0		0
Reserve for uncertain tax positions		$ 0		$ 0		0
Expense ratio	[1]	0.60%	0.60%	0.60%	0.60%
Sponsor Fees		$ 741,934	$ 793,532	$ 2,291,519	$ 2,348,395
Fees payable to Sponsor		247,537		$ 247,537		$ 285,960
All other expenses		$ 0	$ 0

[1] Annualized for periods of less than one year.