Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	[1]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment	[1]	Accumulated other comprehensive income (loss):
AOCI, beginning balance at Dec. 31, 2019	$ 11,022	$ 1		$ 5	$ 33	$ 11,022	$ 1		$ (38)
Beginning balance, shares at Dec. 31, 2019				548
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	367					367
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(226)
Other comprehensive income (loss)	(226)
Common stock issued, stock-based compensation plans - value	40				40
Common stock issued, stock-based compensation plans - shares				2
Stock-based compensation expense	55				55
Repurchases of common stock, Value	(526)				(87)	(439)
Repurchases of common stock, Shares				(9)
Dividends declared, $0.24 per share	(120)					(120)
AOCI, ending balance at Mar. 31, 2020	10,613			$ 5	41	10,831			(264)
Ending balance, shares at Mar. 31, 2020				541
AOCI, beginning balance at Dec. 31, 2019	11,022	$ 1		$ 5	33	11,022	$ 1		(38)
Beginning balance, shares at Dec. 31, 2019				548
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	728
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(150)								(150)
AOCI, ending balance at Jun. 30, 2020	10,972			$ 5	83	11,072			(188)
Ending balance, shares at Jun. 30, 2020				542
AOCI, beginning balance at Mar. 31, 2020	10,613			$ 5	41	10,831			(264)
Beginning balance, shares at Mar. 31, 2020				541
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	361					361
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	76								76
Other comprehensive income (loss)	76
Common stock issued, stock-based compensation plans - value	36				36
Common stock issued, stock-based compensation plans - shares				2
Stock-based compensation expense	65				65
Repurchases of common stock, Value	(59)				(59)	0
Repurchases of common stock, Shares				(1)
Dividends declared, $0.24 per share	(120)					(120)
AOCI, ending balance at Jun. 30, 2020	10,972			$ 5	83	11,072			(188)
Ending balance, shares at Jun. 30, 2020				542
AOCI, beginning balance at Dec. 31, 2020	$ 10,836			$ 5	32	10,689			110
Beginning balance, shares at Dec. 31, 2020	530			530
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 505					505
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(29)
Other comprehensive income (loss)	(29)
Common stock issued, stock-based compensation plans - value	43				43
Common stock issued, stock-based compensation plans - shares				1
Stock-based compensation expense	62				62
Repurchases of common stock, Value	(252)				(93)	(159)
Repurchases of common stock, Shares				(3)
Dividends declared, $0.24 per share	(128)					(128)
AOCI, ending balance at Mar. 31, 2021	11,037			$ 5	44	10,907			81
Ending balance, shares at Mar. 31, 2021				528
AOCI, beginning balance at Dec. 31, 2020	$ 10,836			$ 5	32	10,689			110
Beginning balance, shares at Dec. 31, 2020	530			530
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 1,017
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(28)								(28)
AOCI, ending balance at Jun. 30, 2021	$ 11,205			$ 5	32	11,086			82
Ending balance, shares at Jun. 30, 2021	525			525
AOCI, beginning balance at Mar. 31, 2021	$ 11,037			$ 5	44	10,907			81
Beginning balance, shares at Mar. 31, 2021				528
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	512
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1								1
Other comprehensive income (loss)	1
Common stock issued, stock-based compensation plans - value	32				32
Common stock issued, stock-based compensation plans - shares				1
Stock-based compensation expense	67				67
Repurchases of common stock, Value	(316)				(111)	(205)
Repurchases of common stock, Shares				(4)
Dividends declared, $0.24 per share	(128)					(128)
AOCI, ending balance at Jun. 30, 2021	$ 11,205			$ 5	$ 32	$ 11,086			$ 82
Ending balance, shares at Jun. 30, 2021	525			525

[1] Reflects    the adoption of the Credit Loss Standard on January 1, 2020. Refer to the notes in the consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2020.