REVENUE

The following table disaggregates our revenue by major source for the periods ended March 31 (in millions):



	First Quarter 2018
	Automotive		Mobility		Ford Credit		Consolidated
Vehicles, parts, and accessories	$	37,417	$	—	$	—	$	37,417
Used vehicles	928		—		—		928
Extended service contracts	329		—		—		329
Other revenue	219		4		55		278
Revenues from sales and services	38,893		4		55		38,952

Leasing income	119		—		1,415		1,534
Financing income	—		—		1,432		1,432
Insurance income	—		—		41		41
Total revenues	$	39,012	$	4	$	2,943	$	41,959

	First Quarter 2019
	Automotive		Mobility		Ford Credit		Consolidated
Vehicles, parts, and accessories	$	35,576	$	—	$	—	$	35,576
Used vehicles	1,020		—		—		1,020
Extended service contracts	333		—		—		333
Other revenue	213		6		51		270
Revenues from sales and services	37,142		6		51		37,199

Leasing income	97		—		1,477		1,574
Financing income	—		—		1,528		1,528
Insurance income	—		—		41		41
Total revenues	$	37,239	$	6	$	3,097	$	40,342

The amount of consideration we receive and revenue we recognize on our vehicles, parts, and accessories varies with changes in marketing incentives and returns we offer to our customers and their customers. As a result of changes in our estimate of marketing incentives, we recorded a decrease related to revenue recognized in prior periods of $718 million and $481 million in the first quarter of 2018 and 2019, respectively.

We sell separately-priced service contracts that extend mechanical and maintenance coverages beyond our base warranty agreements to vehicle owners (“extended service contracts”). At December 31, 2017 and December 31, 2018, $3.8 billion and $4 billion, respectively, of unearned revenue associated with outstanding contracts was reported in Other liabilities and deferred revenue. We recognized $298 million and $305 million of the unearned amounts as revenue during the first quarter of 2018 and 2019, respectively. At March 31, 2019, the unearned amount was $4 billion. We expect to recognize approximately $900 million of the unearned amount in the remainder of 2019, $1.1 billion in 2020, and $2 billion thereafter.

Amounts paid to dealers to obtain these contracts are deferred and recorded as Other assets. We had a balance of $247 million and $256 million in deferred costs as of December 31, 2018 and March 31, 2019, respectively, and recognized $18 million and $19 million of amortization during the first quarter of 2018 and 2019, respectively.