Expense Example (Total Bond Market Trust A, USD $)	12 Months Ended
May 01, 2011
Series I, Total Bond Market Trust A
Expense Example:
Year 1	$ 55
Year 3	173
Year 5	302
Year 10	677
Series II, Total Bond Market Trust A
Expense Example:
Year 1	76
Year 3	237
Year 5	411
Year 10	918
Series NAV, Total Bond Market Trust A
Expense Example:
Year 1	50
Year 3	157
Year 5	274
Year 10	$ 616

Name:	rr_ExpenseExampleAbstract
Namespace Prefix:	rr
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.

+ References

Reference 1: 1
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 3
-Paragraph 4
-Subsection instructions

+ Details

Name:	rr_ExpenseExampleYear01
Namespace Prefix:	rr
Data Type:	rr:NonNegativeMonetaryType
Balance Type:	na
Period Type:	duration

- Definition

+ References

Reference 1: 1
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 3
-Paragraph 1
-Subparagraph 2
-Subsection example

+ Details

Name:	rr_ExpenseExampleYear03
Namespace Prefix:	rr
Data Type:	rr:NonNegativeMonetaryType
Balance Type:	na
Period Type:	duration

- Definition

+ References

Reference 1: 1
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 3
-Paragraph 1
-Subparagraph 2
-Subsection example

+ Details

Name:	rr_ExpenseExampleYear05
Namespace Prefix:	rr
Data Type:	rr:NonNegativeMonetaryType
Balance Type:	na
Period Type:	duration

- Definition

+ References

Reference 1: 1
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 3
-Paragraph 1
-Subparagraph 2
-Subsection example

+ Details

Name:	rr_ExpenseExampleYear10
Namespace Prefix:	rr
Data Type:	rr:NonNegativeMonetaryType
Balance Type:	na
Period Type:	duration