Investments - Detail of equity method investments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Schedule of Investments [Line Items]
Investments accounted for using the equity method	$ 1,378		$ 1,378		$ 1,235
Equity in earnings of partnerships and similar investments	71	$ (6)	149	$ 17
Real estate-related investments
Schedule of Investments [Line Items]
Investments accounted for using the equity method	1,014		1,014		915
Equity in earnings of partnerships and similar investments	45	13	99	38
Private equity
Schedule of Investments [Line Items]
Investments accounted for using the equity method	314		314		266
Equity in earnings of partnerships and similar investments	24	(13)	45	(17)
Private debt
Schedule of Investments [Line Items]
Investments accounted for using the equity method	50		50		$ 54
Equity in earnings of partnerships and similar investments	$ 2	$ (6)	$ 5	$ (4)