| Date | Acquired | Amount |
|---|---|---|
| Aug 27, 2017 |
|
Undisclosed amount |
| Jul 21, 2016 |
|
$ 2,500,000,000 |
| Oct 17, 2012 |
|
Undisclosed amount |
| Dec 14, 2009 |
|
$ 41,000,000,000 |
