Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2023 |
Dec. 31, 2022 |
|
| Fair Value, Nonrecurring [Member] | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Goodwill and Intangible Asset Impairment | $ 0 | $ 0 |
| Residential Mortgage Backed Securities - Agency [Member] | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Available for sale security, par value | $ 480 | |
| Available for sale securities, weighted average coupon rate (in percent) | 4.09% | |
| Available for sale securities, weighted average remaining maturity (in years) | 4 years | |