STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST	6 Months Ended
Jun. 30, 2017
Stockholders' Equity Attributable to Parent [Abstract]
STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST	STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST Stockholders' Equity Components of Comprehensive Income (Loss) Comprehensive income (loss) includes: foreign currency translation adjustments; market value adjustments, which represent unrealized holding gains (losses) on available-for-sale securities, net of taxes; and net deferred loss on cash flow hedges, which represents deferred losses, net of taxes on interest rate related derivative financial instruments designated as cash flow hedges, net of amounts reclassified to interest expense (see Note 8). For the three and six months ended June 30, 2017 and 2016, the tax effects related to the deferred losses on cash flow hedges and market valuation adjustments were not material. Foreign currency translation adjustments are not adjusted for income taxes since they relate to indefinite investments in non-U.S. subsidiaries. Dividend Program During the first and second quarters of 2017, the Company's Board of Directors declared a quarterly cash dividend of $0.45 per common share. During each of the first three quarters of 2016, the Company's Board of Directors declared a quarterly cash dividend of $0.40 per common share. During the fourth quarter of 2016, the Company's Board of Directors declared a quarterly cash dividend of $0.45 per common share. Share Repurchase Program As of June 30, 2017, $1.1 billion remained available under the Company’s share repurchase authorizations. The share repurchase authorization has no set expiration or termination date. Share Repurchases For the six months ended June 30, 2017, the Company repurchased 3.0 million shares of its common stock for $300 million. For the six months ended June 30, 2016, the Company repurchased 4.8 million shares of its common stock for $352 million, including 2.8 million shares repurchased under an accelerated share repurchase agreement ("ASR") as follows: In May 2016, the Company entered into an ASR with a financial institution to repurchase $250 million of the Company's common stock as part of the Company's share repurchase program. The ASR was structured as a combination of two transactions: (1) a treasury stock repurchase; and (2) a forward contract, which permitted the Company to purchase shares immediately with the final purchase price of those shares determined by the volume weighted average price of the Company's common stock during the repurchase period, less a fixed discount. Under the ASR, the Company paid $250 million to the financial institution and received 3.1 million shares of common stock, resulting in a final price per share of $81.04. The Company initially received 2.8 million shares of its common stock during the second quarter of 2016 and received an additional 0.3 million shares upon completion of the ASR during the third quarter of 2016. As of June 30, 2016, the Company recorded this transaction as an increase to treasury stock for $212 million, and recorded the remaining $38 million as a decrease to additional paid-in capital. Upon completion of the ASR in the third quarter of 2016, the Company reclassified the $38 million to treasury stock from additional paid-in capital. Shares Reissued from Treasury Stock For the six months ended June 30, 2017 and 2016, the Company reissued 1.8 million shares and 0.9 million shares, respectively, from treasury stock for employee benefit plans. Redeemable Noncontrolling Interest In connection with the sale of an 18.9% noncontrolling interest in a subsidiary to UMass Memorial Medical Center ("UMass") on July 1, 2015, the Company granted UMass the right to require the Company to purchase all of its interest in the subsidiary at fair value commencing July 1, 2020. The subsidiary performs diagnostic information services in a defined territory within the state of Massachusetts. Since the redemption of the noncontrolling interest is outside of the Company's control, it has been presented outside of stockholders' equity at the greater of its carrying amount or its fair value. The Company will record changes in the fair value of the noncontrolling interest immediately as they occur. As of June 30, 2017, the redeemable noncontrolling interest was presented at its fair value.

STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST

Stockholders' Equity

Components of Comprehensive Income (Loss)

Comprehensive income (loss) includes: foreign currency translation adjustments; market value adjustments, which represent unrealized holding gains (losses) on available-for-sale securities, net of taxes; and net deferred loss on cash flow hedges, which represents deferred losses, net of taxes on interest rate related derivative financial instruments designated as cash flow hedges, net of amounts reclassified to interest expense (see Note 8). For the three and six months ended June 30, 2017 and 2016, the tax effects related to the deferred losses on cash flow hedges and market valuation adjustments were not material. Foreign currency translation adjustments are not adjusted for income taxes since they relate to indefinite investments in non-U.S. subsidiaries.

Dividend Program

During the first and second quarters of 2017, the Company's Board of Directors declared a quarterly cash dividend of $0.45 per common share. During each of the first three quarters of 2016, the Company's Board of Directors declared a quarterly cash dividend of $0.40 per common share. During the fourth quarter of 2016, the Company's Board of Directors declared a quarterly cash dividend of $0.45 per common share.

Share Repurchase Program

As of June 30, 2017, $1.1 billion remained available under the Company’s share repurchase authorizations. The share repurchase authorization has no set expiration or termination date.

Share Repurchases

For the six months ended June 30, 2017, the Company repurchased 3.0 million shares of its common stock for $300 million.

For the six months ended June 30, 2016, the Company repurchased 4.8 million shares of its common stock for $352 million, including 2.8 million shares repurchased under an accelerated share repurchase agreement ("ASR") as follows:

In May 2016, the Company entered into an ASR with a financial institution to repurchase $250 million of the Company's common stock as part of the Company's share repurchase program. The ASR was structured as a combination of two transactions: (1) a treasury stock repurchase; and (2) a forward contract, which permitted the Company to purchase shares immediately with the final purchase price of those shares determined by the volume weighted average price of the Company's common stock during the repurchase period, less a fixed discount. Under the ASR, the Company paid $250 million to the financial institution and received 3.1 million shares of common stock, resulting in a final price per share of $81.04. The Company initially received 2.8 million shares of its common stock during the second quarter of 2016 and received an additional 0.3 million shares upon completion of the ASR during the third quarter of 2016. As of June 30, 2016, the Company recorded this transaction as an increase to treasury stock for $212 million, and recorded the remaining $38 million as a decrease to additional paid-in capital. Upon completion of the ASR in the third quarter of 2016, the Company reclassified the $38 million to treasury stock from additional paid-in capital.

Shares Reissued from Treasury Stock

For the six months ended June 30, 2017 and 2016, the Company reissued 1.8 million shares and 0.9 million shares, respectively, from treasury stock for employee benefit plans.

Redeemable Noncontrolling Interest

In connection with the sale of an 18.9% noncontrolling interest in a subsidiary to UMass Memorial Medical Center ("UMass") on July 1, 2015, the Company granted UMass the right to require the Company to purchase all of its interest in the subsidiary at fair value commencing July 1, 2020. The subsidiary performs diagnostic information services in a defined territory within the state of Massachusetts. Since the redemption of the noncontrolling interest is outside of the Company's control, it has been presented outside of stockholders' equity at the greater of its carrying amount or its fair value. The Company will record changes in the fair value of the noncontrolling interest immediately as they occur. As of June 30, 2017, the redeemable noncontrolling interest was presented at its fair value.