Business, Basis of Presentation and Significant Accounting Policies Narrative (Details) - Forecast [Member] - Accounting Standards Update 2016-13 [Member] $ in Millions	Jan. 01, 2020 USD ($)
Retained earnings | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 140
Retained earnings | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 240
Commercial mortgage loans | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement effect, percentage	1.40%
Commercial mortgage loans | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement effect, percentage	2.50%