| Date | Acquired | Amount |
|---|---|---|
| Mar 31, 2016 |
|
Undisclosed amount |
| Sep 23, 2015 |
|
$ 2,450,000,000 |
| May 21, 2015 |
|
Undisclosed amount |
| Apr 30, 2001 |
|
$ 171,000,000 |
| Jul 28, 1998 |
|
$ 1,800,000,000 |
