Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies.

Changes to Gross Insurance Liabilities

The changes to our insurance reserves for the years ended December 31 are summarized below (in millions):

	2017(a)		2016
Balance as of January 1	$	588	$	643
Self-insurance expense		142		71
Cash paid		(148)		(126)
Balance as of December 31	$	582	$	588
Current portion as of December 31	$	107	$	133
Long-term portion as of December 31	$	475	$	455

(a) Based on current estimates, we anticipate that most of our insurance reserves will be settled in cash over the next six years.