Here is the line of succession after the US President -->

1 Vice President of the United States Joe Biden (D)
2 Speaker of the House John Boehner (R)
3 President pro tempore of the Senate Orrin Hatch (R)
4 Secretary of State John Kerry (D)
5 Secretary of the Treasury Jacob Lew (D)
6 Secretary of Defense Ashton Carter (D)
7 Attorney General Loretta Lynch (D)
— Secretary of the Interior Sally Jewell (D)[Not a natural-born citizen & thus not eligible]
8 Secretary of Agriculture Tom Vilsack (D)
9 Secretary of Commerce Penny Pritzker (D)
10 Secretary of Labor Thomas Perez (D)
11 Secretary of Health and Human Services Sylvia Mathews Burwell (D)
12 Secretary of Housing and Urban Development Julián Castro (D)
13 Secretary of Transportation Anthony Foxx (D)
14 Secretary of Energy Ernest Moniz (D)
15 Secretary of Education Arne Duncan (D)
16 Secretary of Veterans Affairs Robert McDonald (R)
17 Secretary of Homeland Security Jeh Johnson (D)