Debt Securities (Tables)
|
9 Months Ended |
Sep. 30, 2026 |
|---|
| Investments, Debt and Equity Securities [Abstract] |
|
| Investments in Debt Securities, Classified as Available-For-Sale |
Investments in debt securities, classified as available-for-sale, are as follows:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Amortized |
|
|
Gross unrealized |
|
|
Estimated |
|
(in millions) |
|
cost |
|
|
Gains |
|
|
Losses |
|
|
fair value |
|
September 30, 2026 |
|
|
|
|
|
|
|
|
|
|
|
|
U.S. Treasury bonds |
|
$ |
257.0 |
|
|
$ |
— |
|
|
$ |
(9.5 |
) |
|
$ |
247.5 |
|
Municipal bonds |
|
|
1,146.3 |
|
|
|
0.6 |
|
|
|
(117.7 |
) |
|
$ |
1,029.2 |
|
Foreign government bonds |
|
|
241.8 |
|
|
|
0.3 |
|
|
|
(5.8 |
) |
|
$ |
236.3 |
|
Governmental agency bonds |
|
|
474.3 |
|
|
|
— |
|
|
|
(30.3 |
) |
|
$ |
444.0 |
|
Governmental agency mortgage-backed securities |
|
|
6,623.2 |
|
|
|
0.6 |
|
|
|
(529.6 |
) |
|
$ |
6,094.2 |
|
U.S. corporate debt securities |
|
|
1,299.1 |
|
|
|
0.8 |
|
|
|
(65.6 |
) |
|
$ |
1,234.3 |
|
Foreign corporate debt securities |
|
|
493.5 |
|
|
|
1.2 |
|
|
|
(17.6 |
) |
|
$ |
477.1 |
|
|
|
$ |
10,535.2 |
|
|
$ |
3.5 |
|
|
$ |
(776.1 |
) |
|
$ |
9,762.6 |
|
December 31, 2025 |
|
|
|
|
|
|
|
|
|
|
|
|
U.S. Treasury bonds |
|
$ |
244.2 |
|
|
$ |
1.0 |
|
|
$ |
(1.6 |
) |
|
$ |
243.6 |
|
Municipal bonds |
|
|
1,003.5 |
|
|
|
9.9 |
|
|
|
(53.3 |
) |
|
|
960.1 |
|
Foreign government bonds |
|
|
239.4 |
|
|
|
1.1 |
|
|
|
(5.3 |
) |
|
|
235.2 |
|
Governmental agency bonds |
|
|
268.3 |
|
|
|
0.3 |
|
|
|
(7.6 |
) |
|
|
261.0 |
|
Governmental agency mortgage-backed securities |
|
|
5,401.9 |
|
|
|
41.9 |
|
|
|
(183.0 |
) |
|
|
5,260.8 |
|
U.S. corporate debt securities |
|
|
1,032.8 |
|
|
|
15.7 |
|
|
|
(13.7 |
) |
|
|
1,034.8 |
|
Foreign corporate debt securities |
|
|
466.6 |
|
|
|
9.5 |
|
|
|
(4.9 |
) |
|
|
471.2 |
|
|
|
$ |
8,656.7 |
|
|
$ |
79.4 |
|
|
$ |
(269.4 |
) |
|
$ |
8,466.7 |
|
|
| Gross Unrealized Losses on Investments in Debt Securities |
Investments in debt securities in an unrealized loss position, and their respective length of time in such position, are as follows:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Less than 12 months |
|
|
12 months or longer |
|
|
Total |
|
(in millions) |
|
Estimated
fair value |
|
|
Unrealized
losses |
|
|
Estimated
fair value |
|
|
Unrealized
losses |
|
|
Estimated
fair value |
|
|
Unrealized
losses |
|
September 30, 2026 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
U.S. Treasury bonds |
|
$ |
230.1 |
|
|
$ |
(8.5 |
) |
|
$ |
17.2 |
|
|
$ |
(1.0 |
) |
|
$ |
247.3 |
|
|
$ |
(9.5 |
) |
Municipal bonds |
|
|
619.2 |
|
|
|
(36.6 |
) |
|
|
385.9 |
|
|
|
(81.1 |
) |
|
|
1,005.1 |
|
|
|
(117.7 |
) |
Foreign government bonds |
|
|
148.2 |
|
|
|
(1.9 |
) |
|
|
34.9 |
|
|
|
(3.9 |
) |
|
|
183.1 |
|
|
|
(5.8 |
) |
Governmental agency bonds |
|
|
419.2 |
|
|
|
(23.8 |
) |
|
|
24.8 |
|
|
|
(6.5 |
) |
|
|
444.0 |
|
|
|
(30.3 |
) |
Governmental agency mortgage-backed
securities |
|
|
4,850.6 |
|
|
|
(294.9 |
) |
|
|
1,196.9 |
|
|
|
(234.7 |
) |
|
|
6,047.5 |
|
|
|
(529.6 |
) |
U.S. corporate debt securities |
|
|
1,021.8 |
|
|
|
(48.2 |
) |
|
|
72.1 |
|
|
|
(17.4 |
) |
|
|
1,093.9 |
|
|
|
(65.6 |
) |
Foreign corporate debt securities |
|
|
361.7 |
|
|
|
(11.6 |
) |
|
|
39.0 |
|
|
|
(6.0 |
) |
|
|
400.7 |
|
|
|
(17.6 |
) |
|
|
$ |
7,650.8 |
|
|
$ |
(425.5 |
) |
|
$ |
1,770.8 |
|
|
$ |
(350.6 |
) |
|
$ |
9,421.6 |
|
|
$ |
(776.1 |
) |
December 31, 2025 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
U.S. Treasury bonds |
|
$ |
61.7 |
|
|
$ |
(0.3 |
) |
|
$ |
36.3 |
|
|
$ |
(1.3 |
) |
|
$ |
98.0 |
|
|
$ |
(1.6 |
) |
Municipal bonds |
|
|
118.6 |
|
|
|
(1.1 |
) |
|
|
451.3 |
|
|
|
(52.2 |
) |
|
|
569.9 |
|
|
|
(53.3 |
) |
Foreign government bonds |
|
|
76.2 |
|
|
|
(0.3 |
) |
|
|
59.8 |
|
|
|
(5.0 |
) |
|
|
136.0 |
|
|
|
(5.3 |
) |
Governmental agency bonds |
|
|
210.6 |
|
|
|
(1.5 |
) |
|
|
28.9 |
|
|
|
(6.1 |
) |
|
|
239.5 |
|
|
|
(7.6 |
) |
Governmental agency mortgage-backed
securities |
|
|
988.8 |
|
|
|
(9.8 |
) |
|
|
1,479.1 |
|
|
|
(173.2 |
) |
|
|
2,467.9 |
|
|
|
(183.0 |
) |
U.S. corporate debt securities |
|
|
169.4 |
|
|
|
(0.8 |
) |
|
|
101.2 |
|
|
|
(12.9 |
) |
|
|
270.6 |
|
|
|
(13.7 |
) |
Foreign corporate debt securities |
|
|
32.3 |
|
|
|
(0.2 |
) |
|
|
69.0 |
|
|
|
(4.7 |
) |
|
|
101.3 |
|
|
|
(4.9 |
) |
|
|
$ |
1,657.6 |
|
|
$ |
(14.0 |
) |
|
$ |
2,225.6 |
|
|
$ |
(255.4 |
) |
|
$ |
3,883.2 |
|
|
$ |
(269.4 |
) |
|
| Investments in Debt Securities by Contractual Maturity |
Investments in debt securities at September 30, 2026, by contractual maturities, are as follows:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(in millions) |
|
Due in one
year or less |
|
|
Due after
one through
five years |
|
|
Due after
five through
ten years |
|
|
Due after
ten years |
|
|
Total |
|
U.S. Treasury bonds |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Amortized cost |
|
$ |
39.8 |
|
|
$ |
162.2 |
|
|
$ |
50.9 |
|
|
$ |
4.1 |
|
|
$ |
257.0 |
|
Estimated fair value |
|
$ |
39.7 |
|
|
$ |
157.1 |
|
|
$ |
47.6 |
|
|
$ |
3.1 |
|
|
$ |
247.5 |
|
Municipal bonds |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Amortized cost |
|
|
7.2 |
|
|
|
149.4 |
|
|
|
574.0 |
|
|
|
415.7 |
|
|
|
1,146.3 |
|
Estimated fair value |
|
|
7.2 |
|
|
|
141.3 |
|
|
|
509.4 |
|
|
|
371.3 |
|
|
|
1,029.2 |
|
Foreign government bonds |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Amortized cost |
|
|
93.2 |
|
|
|
101.8 |
|
|
|
33.6 |
|
|
|
13.2 |
|
|
|
241.8 |
|
Estimated fair value |
|
|
93.4 |
|
|
|
98.0 |
|
|
|
33.1 |
|
|
|
11.8 |
|
|
|
236.3 |
|
Governmental agency bonds |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Amortized cost |
|
|
— |
|
|
|
0.8 |
|
|
|
272.9 |
|
|
|
200.6 |
|
|
|
474.3 |
|
Estimated fair value |
|
|
— |
|
|
|
0.8 |
|
|
|
259.8 |
|
|
|
183.4 |
|
|
|
444.0 |
|
U.S. corporate debt securities |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Amortized cost |
|
|
3.1 |
|
|
|
590.7 |
|
|
|
533.2 |
|
|
|
172.1 |
|
|
|
1,299.1 |
|
Estimated fair value |
|
|
3.1 |
|
|
|
576.8 |
|
|
|
505.3 |
|
|
|
149.1 |
|
|
|
1,234.3 |
|
Foreign corporate debt securities |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Amortized cost |
|
|
17.3 |
|
|
|
274.6 |
|
|
|
152.6 |
|
|
|
49.0 |
|
|
|
493.5 |
|
Estimated fair value |
|
|
17.2 |
|
|
|
269.8 |
|
|
|
146.5 |
|
|
|
43.6 |
|
|
|
477.1 |
|
Total debt securities (excluding mortgage-backed
securities) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Amortized cost |
|
$ |
160.6 |
|
|
$ |
1,279.5 |
|
|
$ |
1,617.2 |
|
|
$ |
854.7 |
|
|
$ |
3,912.0 |
|
Estimated fair value |
|
$ |
160.6 |
|
|
$ |
1,243.8 |
|
|
$ |
1,501.7 |
|
|
$ |
762.3 |
|
|
$ |
3,668.4 |
|
Total mortgage-backed securities |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Amortized cost |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
6,623.2 |
|
Estimated fair value |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
6,094.2 |
|
Total debt securities |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Amortized cost |
|
|
|
|
|
|
|
|
|
|
|
|
|
$ |
10,535.2 |
|
Estimated fair value |
|
|
|
|
|
|
|
|
|
|
|
|
|
$ |
9,762.6 |
|
|
| Composition of Debt Securities Portfolio by Credit Rating Agencies |
The composition of the debt securities portfolio at September 30, 2026, by credit rating, is as follows:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
A- or higher |
|
|
BBB+ to BBB- |
|
|
Non-Investment Grade |
|
|
Total |
|
(dollars in millions) |
|
Estimated
fair value |
|
|
Percentage |
|
|
Estimated
fair value |
|
|
Percentage |
|
|
Estimated
fair value |
|
|
Percentage |
|
|
Estimated
fair value |
|
U.S. Treasury bonds |
|
$ |
247.5 |
|
|
|
100.0 |
% |
|
$ |
— |
|
|
|
— |
% |
|
$ |
— |
|
|
|
— |
% |
|
$ |
247.5 |
|
Municipal bonds |
|
|
1,014.1 |
|
|
|
98.6 |
|
|
|
14.8 |
|
|
|
1.4 |
|
|
|
0.3 |
|
|
|
— |
|
|
|
1,029.2 |
|
Foreign government bonds |
|
|
228.1 |
|
|
|
96.5 |
|
|
|
7.5 |
|
|
|
3.2 |
|
|
|
0.7 |
|
|
|
0.3 |
|
|
|
236.3 |
|
Governmental agency bonds |
|
|
444.0 |
|
|
|
100.0 |
|
|
|
— |
|
|
|
— |
|
|
|
— |
|
|
|
— |
|
|
|
444.0 |
|
Governmental agency mortgage-
backed securities |
|
|
6,094.2 |
|
|
|
100.0 |
|
|
|
— |
|
|
|
— |
|
|
|
— |
|
|
|
— |
|
|
|
6,094.2 |
|
U.S. corporate debt securities |
|
|
786.8 |
|
|
|
63.7 |
|
|
|
302.4 |
|
|
|
24.5 |
|
|
|
145.1 |
|
|
|
11.8 |
|
|
|
1,234.3 |
|
Foreign corporate debt securities |
|
|
264.7 |
|
|
|
55.5 |
|
|
|
185.5 |
|
|
|
38.9 |
|
|
|
26.9 |
|
|
|
5.6 |
|
|
|
477.1 |
|
|
|
$ |
9,079.4 |
|
|
|
93.0 |
% |
|
$ |
510.2 |
|
|
|
5.2 |
% |
|
$ |
173.0 |
|
|
|
1.8 |
% |
|
$ |
9,762.6 |
|
|
| Composition of Debt Securities Portfolio in Unrealized Loss Position by Credit Rating Agencies |
The composition of the debt securities portfolio in an unrealized loss position at September 30, 2026, by credit rating, is as follows:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
A- or higher |
|
|
BBB+ to BBB- |
|
|
Non-Investment Grade |
|
|
Total |
|
(dollars in millions) |
|
Estimated
fair value |
|
|
Percentage |
|
|
Estimated
fair value |
|
|
Percentage |
|
|
Estimated
fair value |
|
|
Percentage |
|
|
Estimated
fair value |
|
U.S. Treasury bonds |
|
$ |
247.3 |
|
|
|
100.0 |
% |
|
$ |
— |
|
|
|
— |
% |
|
$ |
— |
|
|
|
— |
% |
|
$ |
247.3 |
|
Municipal bonds |
|
|
991.5 |
|
|
|
98.7 |
|
|
|
13.3 |
|
|
|
1.3 |
|
|
|
0.3 |
|
|
|
— |
|
|
|
1,005.1 |
|
Foreign government bonds |
|
|
174.9 |
|
|
|
95.5 |
|
|
|
7.5 |
|
|
|
4.1 |
|
|
|
0.7 |
|
|
|
0.4 |
|
|
|
183.1 |
|
Governmental agency bonds |
|
|
444.0 |
|
|
|
100.0 |
|
|
|
— |
|
|
|
— |
|
|
|
— |
|
|
|
— |
|
|
|
444.0 |
|
Governmental agency mortgage-
backed securities |
|
|
6,047.5 |
|
|
|
100.0 |
|
|
|
— |
|
|
|
— |
|
|
|
— |
|
|
|
— |
|
|
|
6,047.5 |
|
U.S. corporate debt securities |
|
|
720.3 |
|
|
|
65.8 |
|
|
|
273.0 |
|
|
|
25.0 |
|
|
|
100.6 |
|
|
|
9.2 |
|
|
|
1,093.9 |
|
Foreign corporate debt securities |
|
|
227.3 |
|
|
|
56.7 |
|
|
|
155.6 |
|
|
|
38.9 |
|
|
|
17.8 |
|
|
|
4.4 |
|
|
|
400.7 |
|
|
|
$ |
8,852.8 |
|
|
|
93.9 |
% |
|
$ |
449.4 |
|
|
|
4.8 |
% |
|
$ |
119.4 |
|
|
|
1.3 |
% |
|
$ |
9,421.6 |
|
|