Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Restricted Cash and Cash Equivalents

The following table provides a reconciliation of cash, cash equivalents, and restricted cash and cash equivalents reported within the accompanying consolidated balance sheets that sum to the total of the same such amounts presented in the accompanying consolidated statements of cash flows. The restricted cash and cash equivalents presented below are included in non-current “Restricted investments” in the accompanying consolidated balance sheets.

	Nine Months Ended September 30,
	2018		2017
	(In millions)
Cash and cash equivalents	$	2,814	$	3,934
Restricted cash and cash equivalents	94		91
Total cash, cash equivalents, and restricted cash and cash equivalents presented in the statements of cash flows	$	2,908	$	4,025

Schedule of Cash and Cash Equivalents

The following table provides a reconciliation of cash, cash equivalents, and restricted cash and cash equivalents reported within the accompanying consolidated balance sheets that sum to the total of the same such amounts presented in the accompanying consolidated statements of cash flows. The restricted cash and cash equivalents presented below are included in non-current “Restricted investments” in the accompanying consolidated balance sheets.

	Nine Months Ended September 30,
	2018		2017
	(In millions)
Cash and cash equivalents	$	2,814	$	3,934
Restricted cash and cash equivalents	94		91
Total cash, cash equivalents, and restricted cash and cash equivalents presented in the statements of cash flows	$	2,908	$	4,025

Quality incentive premium revenue recognized

The following table quantifies the quality incentive premium revenue recognized for the periods presented, including the amounts earned in the periods presented and prior periods. Although the reasonably possible effects of a change in estimate related to quality incentive premium revenue as of September 30, 2018 are not known, we have no reason to believe that the adjustments to prior years noted below are not indicative of the potential future changes in our estimates as of September 30, 2018.

	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
	(Dollars in millions)
Maximum available quality incentive premium - current period	$	48		$	36		$	135		$	113
Quality incentive premium revenue recognized in current period:
Earned current period	$	39		$	24		$	97		$	72
Earned prior periods	9			3			32			9
Total	$	48		$	27		$	129		81
Quality incentive premium revenue recognized as a percentage of total premium revenue	1.1		%	0.6		%	1.0		%	0.6		%