Fair Value Disclosures (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Estimated Fair Values and Carrying Amounts of Assets and Liabilities

	Level in Fair Value Hierarchy	September 30, 2018				December 31, 2017
		Carrying  Amount		Fair Value		Carrying  Amount		Fair Value
Assets:
Cash and cash equivalents	1	$	323	$	323	$	314	$	314
Restricted cash, current and non-current	1	130		130		126		126
Liabilities:
Total debt and other obligations	2	16,424		16,362		16,159		16,644