Investments (Limited Partnerships and Real Estate Joint Ventures) (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Real Estate [Line Items]
Real Estate Investments, Joint Ventures	$ 3,338	$ 3,067
Equity Method Investments
Real Estate [Line Items]
Real Estate Investments, Joint Ventures	1,195	1,067
Limited partnership Fair Value Member
Real Estate [Line Items]
Real Estate Investments, Joint Ventures	954	966
Corporate Joint Venture
Real Estate [Line Items]
Real Estate Investments, Joint Ventures	1,120	970
Limited Partnership Cost Method
Real Estate [Line Items]
Real Estate Investments, Joint Ventures	$ 69	$ 64

The book value of investments in real estate joint ventures including direct and indirect investments.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(d))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(6))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Name:	us-gaap_RealEstateInvestmentsJointVentures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant