Performance Management - Bond-Debenture Portfolio

Dec. 31, 2025

Prospectus [Line Items]

Bar Chart and Performance Table [Heading]

PERFORMANCE

Performance Narrative [Text Block]

The bar chart and table below provide some indication of the risks of investing in the Fund by illustrating the variability of the Fund’s returns. Each assumes reinvestment of dividends and distributions. The Fund’s past performance is not necessarily an indication of how the Fund will perform in the future.

Performance Past Does Not Indicate Future [Text]

The Fund’s past performance is not necessarily an indication of how the Fund will perform in the future.

Performance Information Illustrates Variability of Returns [Text]

The bar chart and table below provide some indication of the risks of investing in the Fund by illustrating the variability of the Fund’s returns.

Bar Chart Narrative [Text Block]

The bar chart shows changes in the performance of the Fund’s Class VC shares from calendar year to calendar year. This chart does not reflect the sales charges or other expenses of Variable Contracts. If those sales charges and expenses were reflected, returns would be lower.

Bar Chart Does Not Reflect Sales Loads [Text]

This chart does not reflect the sales charges or other expenses of Variable Contracts. If those sales charges and expenses were reflected, returns would be lower.

Bar Chart [Heading]

Bar Chart (per calendar year) - Class VC Shares

Bar Chart Closing [Text Block]

Best Quarter 2nd Q 2020 +10.40%    Worst Quarter 1st Q 2020 -12.42%

Performance Table Heading

Average Annual Total Returns (for the periods ended December 31, 2025)

Performance Table Narrative

The table below shows how the Fund’s average annual total returns compare to the returns of securities market indices with investment characteristics similar to those of the Fund.

Performance [Table]

Average Annual Total Returns - Bond-Debenture Portfolio		12 Months Ended	60 Months Ended	120 Months Ended
	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025
Bloomberg U.S. Aggregate Bond Index | Average Annual Return, Label [Optional Text]	Bloomberg U.S. Aggregate Bond Index
Bloomberg U.S. Aggregate Bond Index | Average Annual Return, Percent		7.30%	(0.36%)	2.01%
ICE BofA U.S. High Yield Constrained Index | Average Annual Return, Label [Optional Text]	ICE BofA U.S. High Yield Constrained Index
ICE BofA U.S. High Yield Constrained Index | Average Annual Return, Percent		8.59%	4.56%	6.47%
VC Shares | Average Annual Return, Percent		8.33%	2.10%	4.72%

Index No Deduction for Fees, Expenses, or Taxes [Text]

(reflects no deduction for fees, expenses, or taxes)

VC Shares

Prospectus [Line Items]

Highest Quarterly Return, Label [Optional Text]

Best Quarter

Highest Quarterly Return

10.40%

Highest Quarterly Return, Date

Jun. 30, 2020

Lowest Quarterly Return, Label [Optional Text]

Worst Quarter

Lowest Quarterly Return

(12.42%)

Lowest Quarterly Return, Date

Mar. 31, 2020