Mortgage Loans - Credit Quality Indicators - MF (Details) - Multifamily - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	$ 50,350	$ 50,494
One fiscal year before	53,930	60,908
Two fiscal years before	58,780	64,398
Three fiscal years before	63,361	75,526
Four fiscal years before	74,319	60,850
Prior	188,987	149,178
Total mortgage loans	489,727	461,354
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	49,867	49,944
One fiscal year before	51,194	51,380
Two fiscal years before	49,570	60,563
Three fiscal years before	59,687	72,791
Four fiscal years before	71,657	56,901
Prior	175,887	136,860
Total mortgage loans	457,862	428,439
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	54	4
One fiscal year before	68	11
Two fiscal years before	165	181
Three fiscal years before	353	32
Four fiscal years before	162	46
Prior	280	130
Total mortgage loans	1,082	404
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	429	521
One fiscal year before	2,626	9,517
Two fiscal years before	9,045	3,654
Three fiscal years before	3,259	2,703
Four fiscal years before	2,500	3,893
Prior	12,820	12,188
Total mortgage loans	30,679	32,476
Substandard | Senior Housing
Financing Receivable, Credit Quality Indicator [Line Items]
Total mortgage loans	3,800	6,900
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	25
One fiscal year before	42	0
Two fiscal years before	0	0
Three fiscal years before	62	0
Four fiscal years before	0	10
Prior	0	0
Total mortgage loans	104	35
Current-year write-offs
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
One fiscal year before	81	3
Two fiscal years before	192	4
Three fiscal years before	16	6
Four fiscal years before	27	23
Prior	189	365
Total mortgage loans	$ 505	$ 401