Statements of Partners' Capital (Parenthetical) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Statements of Partners' Capital [Abstract]
Cash distribution per limited partnership interest	$ 27.77	$ 22.26	$ 25.39

Cash distribution per limited partnership interest.

No definition available.

Name:	zzdd_CashDistributionsPerLimitedPartnershipInterest
Namespace Prefix:	zzdd_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration