Investments - Unrealized Capital Losses 1 (Details) $ in Millions	3 Months Ended
Mar. 31, 2023 USD ($) securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Available For Sale Securities Change in Loss Position \| $	$ (436)
Fair value decline below amortized cost greater than 20%
Available-for-sale Securities Including Securities Pledged [Line Items]
More than twelve months below amortized cost, Number of Securities \| securities	69

Number of investment positions in available-for-sale investments that have been in a continuous unrealized loss position for greater than or equal to a year for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

No definition available.

Name:	us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant