Goodwill and Other Intangible Assets (Details) - Other Intangible Assets - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Other intangible assets by major asset class      
Intangible assets subject to amortization, gross carrying amount $ 298   $ 304
Intangible assets subject to amortization, accumulated amortization 202   200
Intangible assets subject to amortization, net 96   104
Intangible assets not subject to amortization 226   226
Total other intangible assets, gross carrying amount 524   530
Total other intangible assets, net 322   330
Amortization expense of intangible assets 4 $ 4  
Estimated intangible asset amortization expense, remainder of 2020 10    
Estimated intangible asset amortization expense, 2021 13    
Estimated intangible asset amortization expense, 2022 12    
Estimated intangible asset amortization expense, 2023 12    
Estimated intangible asset amortization expense, 2024 11    
Customer-related [Member]      
Other intangible assets by major asset class      
Intangible assets subject to amortization, gross carrying amount 94   99
Intangible assets subject to amortization, accumulated amortization 22   21
Intangible assets subject to amortization, net 72   78
Contract-based [Member]      
Other intangible assets by major asset class      
Intangible assets subject to amortization, gross carrying amount 204   205
Intangible assets subject to amortization, accumulated amortization 180   179
Intangible assets subject to amortization, net 24   $ 26
Insurance Contracts Acquired in Business Combination [Member]      
Other intangible assets by major asset class      
Estimated intangible asset amortization expense, remainder of 2020 4    
Estimated intangible asset amortization expense, 2021 4    
Estimated intangible asset amortization expense, 2022 3    
Estimated intangible asset amortization expense, 2023 3    
Estimated intangible asset amortization expense, 2024 $ 2