Stockholders' Equity and EPS - Reconciliation of Basic EPS to Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net income available to common stockholders	$ 502	$ 229	$ 1,034	$ 361
Denominator:
Weighted average common shares outstanding-basic (in shares)	54,353	51,581	53,272	51,573
Weighted average common shares outstanding—diluted (in shares)	55,152	51,795	54,115	51,848
Earnings per common share:
Basic (dollars per share)	$ 9.23	$ 4.44	$ 19.40	$ 7.00
Diluted (dollars per share)	$ 9.09	$ 4.42	$ 19.10	$ 6.97
Stock options and ESPP
Denominator:
Weighted average effect of dilutive securities (in shares)	272	114	274	140
Restricted stock units and awards
Denominator:
Weighted average effect of dilutive securities (in shares)	527	100	569	135