debt issuance costs : debt issuance costs are reflected as a direct deduction of our long-term debt balance on the consolidated balance sheets .
we incurred debt issuance costs of $ 15 million in 2018 and $ 53 million in 2016 .
debt issuance costs in 2017 were insignificant .
unamortized debt issuance costs were $ 115 million at december 29 , 2018 , $ 114 million at december 30 , 2017 , and $ 124 million at december 31 , 2016 .
amortization of debt issuance costs was $ 16 million in 2018 , $ 16 million in 2017 , and $ 14 million in 2016 .
debt premium : unamortized debt premiums are presented on the consolidated balance sheets as a direct addition to the carrying amount of debt .
unamortized debt premium , net , was $ 430 million at december 29 , 2018 and $ 505 million at december 30 , 2017 .
amortization of our debt premium , net , was $ 65 million in 2018 , $ 81 million in 2017 , and $ 88 million in 2016 .
debt repayments : in july and august 2018 , we repaid $ 2.7 billion aggregate principal amount of senior notes that matured in the period .
we funded these long-term debt repayments primarily with proceeds from the new notes issued in june 2018 .
additionally , in june 2017 , we repaid $ 2.0 billion aggregate principal amount of senior notes that matured in the period .
we funded these long-term debt repayments primarily with cash on hand and our commercial paper programs .
fair value of debt : at december 29 , 2018 , the aggregate fair value of our total debt was $ 30.1 billion as compared with a carrying value of $ 31.2 billion .
at december 30 , 2017 , the aggregate fair value of our total debt was $ 33.0 billion as compared with a carrying value of $ 31.5 billion .
our short-term debt and commercial paper had carrying values that approximated their fair values at december 29 , 2018 and december 30 , 2017 .
we determined the fair value of our long-term debt using level 2 inputs .
fair values are generally estimated based on quoted market prices for identical or similar instruments .
note 20 .
capital stock preferred stock our second amended and restated certificate of incorporation authorizes the issuance of up to 920000 shares of preferred stock .
on june 7 , 2016 , we redeemed all 80000 outstanding shares of our series a preferred stock for $ 8.3 billion .
we funded this redemption primarily through the issuance of long-term debt in may 2016 , as well as other sources of liquidity , including our u.s .
commercial paper program , u.s .
securitization program , and cash on hand .
in connection with the redemption , all series a preferred stock was canceled and automatically retired .
common stock our second amended and restated certificate of incorporation authorizes the issuance of up to 5.0 billion shares of common stock .
shares of common stock issued , in treasury , and outstanding were ( in millions of shares ) : shares issued treasury shares shares outstanding .

shares issued
treasury shares
shares outstanding
balance at january 3 2016
1214
2014
1214
exercise of stock options issuance of other stock awards and other
5
-2 ( 2 )
3
balance at december 31 2016
1219
-2 ( 2 )
1217
exercise of stock options issuance of other stock awards and other
2
2014
2
balance at december 30 2017
1221
-2 ( 2 )
1219
exercise of stock options issuance of other stock awards and other
3
-2 ( 2 )
1
balance at december 29 2018
1224
-4 ( 4 )
1220

.

Question: what is the net increase in outstanding shares during the period of 2016 to 2018 , in millions?
Answer: 6
Calculation: subtract(1220, 1214)