Shares | Weighted- Average Exercise Price | Weighted- Average Remaining Contractual Life | Aggregate Intrinsic Value | ||||||||||
(in millions) | (in years) | (in millions) | |||||||||||
Outstanding at beginning of period | 63 | $ | 45 | ||||||||||
Granted | 8 | 58 | |||||||||||
Exercised | (28 | ) | 44 | ||||||||||
Forfeited | (2 | ) | 55 | ||||||||||
Outstanding at end of period | 41 | 48 | 4.5 | $ | 1,121 | ||||||||
Exercisable at end of period | 30 | 46 | 3.1 | 879 | |||||||||
Vested and expected to vest, end of period | 40 | 48 | 4.5 | 1,110 | |||||||||