| **Non-Insurance Revenues from Contracts with Customers** | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
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| **Revenue from Contract with Customer [Abstract]**       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| Non-Insurance Revenues from Contracts with Customers     | Non-Insurance Revenues from Contracts with CustomersThe Company had deferred non-insurance warranty revenue balances of $3.5 billion and $3.4 billion reported in Deferred non-insurance warranty revenue as of March 31, 2019 and December 31, 2018.  For the three months ended March 31, 2019, the Company recognized $265 million of revenues that were included in the deferred revenue balance as of January 1, 2019.  For the three months ended March 31, 2018, the Company recognized $222 million of revenues that were included in the deferred revenue balance as of January 1, 2018.  For the three months ended March 31, 2019 and 2018, Non-insurance warranty revenue recognized from performance obligations related to prior periods due to a change in estimate was not material.  The Company expects to recognize approximately $754 million of the deferred revenue in the remainder of 2019, $852 million in 2020, $673 million in 2021 and $1.2 billion thereafter. |

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| - References
No definition available.
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| - Definition
The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.
+ References
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