Business, Basis of Presentation and Significant Accounting Policies - Accounting Policy Adoption (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net	$ 409	$ 162		$ 593		$ 1,087
Stockholders' Equity Attributable to Parent	5,030	4,897		4,443		3,435
Accumulated Other Comprehensive Income (Loss)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent	$ 1,423	$ 1,882		1,292		$ 108
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts Receivable, Allowance for Credit Loss			$ 12
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net			2	$ 2
Deferred Tax Assets, Deferred Income			2
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings, Unappropriated
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in retained earnings unappropriated			$ 8
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings, Unappropriated | Adjustment for adoption of ASU 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent					$ (137)
Cumulative Effect, Period of Adoption, Adjustment | Accumulated Other Comprehensive Income (Loss) | Adjustment for adoption of ASU 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent					$ 137