Stockholders' Equity and Accumulated Other Comprehensive Loss (Details) - USD ($) $ / shares in Units, $ in Millions					1 Months Ended				2 Months Ended				3 Months Ended								9 Months Ended	12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Sep. 29, 2018	Aug. 31, 2019	May 31, 2019	Feb. 28, 2019	Aug. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Sep. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components of and changes in accumulated other comprehensive loss, net of tax
Balance at beginning of the period											$ (410)					$ (354)						$ (410)	$ (354)
Other comprehensive income (loss) before reclassifications																						(34)	(53)
Amounts reclassified from accumulated other comprehensive loss to net earnings																						4	4
Other comprehensive income (loss), net of tax																						(30)	(49)
Balance at end of the period													$ (440)	$ (410)			$ (354)					$ (440)	$ (410)	$ (354)
Common shares repurchased (in shares)																						4,369	1,333
Repurchase of common stock																						$ 17	$ 5
Remaining authorized repurchase amount													$ 78									$ 78
Common stock dividend declared and paid (in dollars per share)																						$ 9.00	$ 6.00	$ 6.00
Common stock dividend declared (in dollars per share)	$ 2.25	$ 2.25	$ 2.25	$ 1.50	$ 2.25	$ 2.25	$ 2.25	$ 1.50	$ 2.25	$ 2.25	$ 2.25	$ 1.50	$ 2.25	$ 1.50	$ 1.50	$ 1.50	$ 1.50	$ 1.50	$ 1.50	$ 1.50
ASU 2018-02
Components of and changes in accumulated other comprehensive loss, net of tax
Balance at beginning of the period																$ (45)							$ (45)
Balance at end of the period																	$ (45)							$ (45)
Foreign currency translation adjustment
Components of and changes in accumulated other comprehensive loss, net of tax
Balance at beginning of the period											$ (349)					(297)						$ (349)	(297)
Other comprehensive income (loss) before reclassifications																						(20)	(52)
Other comprehensive income (loss), net of tax																						(20)	(52)
Balance at end of the period													$ (369)	$ (349)			(297)					(369)	(349)	(297)
Unrealized gain on investments
Components of and changes in accumulated other comprehensive loss, net of tax
Balance at beginning of the period																7							7
Balance at end of the period																	7							7
Unrealized gain on investments | ASU 2016-01
Components of and changes in accumulated other comprehensive loss, net of tax
Amounts reclassified from accumulated other comprehensive loss to retained earnings														(7)									(7)
Unrecognized pension cost
Components of and changes in accumulated other comprehensive loss, net of tax
Balance at beginning of the period											$ (61)					$ (64)						(61)	(64)
Other comprehensive income (loss) before reclassifications																						(14)	(1)
Amounts reclassified from accumulated other comprehensive loss to net earnings																						4	4
Other comprehensive income (loss), net of tax																						(10)	3
Balance at end of the period													(71)	(61)			(64)					(71)	(61)	(64)
Accumulated Other Comprehensive Loss
Components of and changes in accumulated other comprehensive loss, net of tax
Amounts reclassified from accumulated other comprehensive loss to retained earnings														(7)			(45)						(7)	(45)
Accumulated Other Comprehensive Loss | ASU 2016-01
Components of and changes in accumulated other comprehensive loss, net of tax
Amounts reclassified from accumulated other comprehensive loss to retained earnings														(7)									(7)
Retained Earnings
Components of and changes in accumulated other comprehensive loss, net of tax
Amounts reclassified from accumulated other comprehensive loss to retained earnings														7			$ 45						7	45
Repurchase of common stock																						$ 17	$ 5
All components of AOCL except cumulative foreign currency translation adjustments
Components of and changes in accumulated other comprehensive loss, net of tax
Effective income tax rate (as a percent)																	26.00%				39.00%	26.00%	26.00%
Certain subsidiaries
Components of and changes in accumulated other comprehensive loss, net of tax
Unrecognized pension cost related to employees at certain subsidiaries													$ 21	$ 23			$ 22					$ 21	$ 23	22
Certain subsidiaries | Unrecognized pension cost
Components of and changes in accumulated other comprehensive loss, net of tax
Tax benefit recorded on unrecognized pension cost																						$ 0	$ 0	$ 0