CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Millions, $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Statement of Financial Position [Abstract]
Amortized cost of investments	$ 29,647.5	$ 29,249.9	[1]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	1,000	1,000
Common stock, shares issued (in shares)	718	718
Common stock, shares outstanding (in shares)	718	718

[1] As of December 31, 2025, the estimated net unrealized gain for federal tax purposes was approximately $300 million based on a tax cost basis of $29.2 billion. As of December 31, 2025, the estimated aggregate gross unrealized gain for federal income tax purposes was approximately $1.3 billion and the estimated aggregate gross unrealized loss for federal income tax purposes was approximately $1.0 billion.