Stockholders' Equity and EPS - Reconciliation of Basic EPS to Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income available to common stockholders	$ 365	$ 442	$ 1,399	$ 803
Denominator:
Weighted average common shares outstanding-basic (in shares)	57,723	51,773	54,772	51,640
Weighted average common shares outstanding—diluted (in shares)	58,521	52,146	55,617	51,950
Earnings per common share:
Basic (dollars per share)	$ 6.33	$ 8.53	$ 25.54	$ 15.55
Diluted (dollars per share)	$ 6.24	$ 8.47	$ 25.16	$ 15.46
Stock options and ESPP
Denominator:
Weighted average effect of dilutive securities (in shares)	268	141	278	147
Restricted stock units and awards
Denominator:
Weighted average effect of dilutive securities (in shares)	530	232	567	163