FAIR VALUE

Financial Assets

The following table summarizes our fair value measurements at June 30, 2018 and December 31, 2017, respectively, for financial assets measured at fair value on a recurring basis:



	Fair Value Measurements Using
	Fair Value		Quoted Prices in Active Markets (Level 1)		Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)
	(in millions)
June 30, 2018
Cash equivalents	$	6,279	$	6,279	$	—	$	—
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations	627		—		627		—
Mortgage-backed securities	2,258		—		2,258		—
Tax-exempt municipal securities	2,999		—		2,999		—
Mortgage-backed securities:
Residential	17		—		17		—
Commercial	517		—		517		—
Asset-backed securities	573		—		573		—
Corporate debt securities	2,852		—		2,852		—
Total debt securities	9,843		—		9,843		—
Total invested assets	$	16,122	$	6,279	$	9,843	$	—

December 31, 2017
Cash equivalents	$	4,564	$	4,564	$	—	$	—
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations	531		—		531		—
Mortgage-backed securities	1,610		—		1,610		—
Tax-exempt municipal securities	3,889		—		3,889		—
Mortgage-backed securities:
Residential	26		—		26		—
Commercial	456		—		456		—
Asset-backed securities	408		—		408		—
Corporate debt securities	5,382		—		5,381		1
Total debt securities	12,302		—		12,301		1
Total invested assets	$	16,866	$	4,564	$	12,301	$	1

There were no material transfers between Level 1 and Level 2 during the three and six months ended June 30, 2018 or 2017. The table above excludes both assets held-for-sale and liabilities held-for-sale, which have been adjusted to fair value, less cost to sell, as a disposal group. See Note 3 for additional disclosures about assets and liabilities held-for-sale at June 30, 2018.

Financial Liabilities

Our debt is recorded at carrying value in our consolidated balance sheets. The carrying value of our senior notes debt outstanding, net of unamortized debt issuance costs, was $4,773 million at June 30, 2018 and $4,770 million at December 31, 2017. The fair value of our senior notes debt was $4,909 million at June 30, 2018 and $5,191 million at December 31, 2017. The fair value of our long-term debt is determined based on Level 2 inputs, including quoted market prices for the same or similar debt, or if no quoted market prices are available, on the current prices estimated to be available to us for debt with similar terms and remaining maturities.

Due to the short-term nature, carrying value approximates fair value for our commercial paper borrowings. There were outstanding commercial paper borrowings of $398 million as of June 30, 2018 and $150 million as of December 31, 2017.

Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis

As disclosed in Note 3, we acquired MCCI, FPG, and other health and wellness related businesses during 2018 and 2017. The values of net tangible assets acquired and the resulting goodwill and other intangible assets were recorded at fair value using Level 3 inputs. The majority of the tangible assets acquired and liabilities assumed were recorded at their carrying values as of the respective dates of acquisition, as their carrying values approximated their fair values due to their short-term nature. The fair values of goodwill and other intangible assets acquired in these acquisitions were internally estimated primarily based on the income approach. The income approach estimates fair value based on the present value of the cash flows that the assets are expected to generate in the future. We developed internal estimates for the expected future cash flows and discount rates used in the present value calculations. Other than assets acquired and liabilities assumed in these acquisitions, there were no material assets or liabilities measured at fair value on a nonrecurring basis during 2018 or 2017.