Non-Insurance Revenues from Contracts with Customers	3 Months Ended
	Mar. 31, 2019
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.