Variable Interest Entities (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Variable Interest Entity [Line Items]
Gains (losses) for consolidated variable interest entities	$ 0	$ 0	$ 0	$ 0
Carrying amount of other investments	4,551		4,551		$ 3,739
Limited Partnerships and Limited Liability Companies [Member]
Variable Interest Entity [Line Items]
Carrying amount of other investments	$ 3,300		$ 3,300		$ 3,100