Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Condensed Financial Statements [Line Items]
Net cash provided by operating activities	[1]			$ 1,081	$ 1,882
Cash flows from investing activities:
Business acquisitions, net of cash acquired				(10,039)	(364)
Capital expenditures				(447)	(273)
Other, net				169	52
Net cash used by investing activities				(10,317)	(585)
Cash flows from financing activities:
Proceeds from notes				6,461	985
Proceeds from (repayments of) commercial paper, net				1,668	(2)
Dividends paid		$ (275)	$ (252)	(801)	(735)
Purchases of common stock				(533)	(1,172)
Repayment of CSRA accounts receivable purchase agreement				(450)	0
Other, net				(68)	41
Net cash provided (used) by financing activities				7,277	(881)
Net cash used by discontinued operations				(14)	(28)
Cash sweep/funding by parent				0	0
Net increase in cash and equivalents				(1,973)	388
Cash and equivalents at beginning of period				2,983	2,334
Cash and equivalents at end of period		1,010	2,722	1,010	2,722
LIBOR
Cash flows from financing activities:
Proceeds from notes				1,000	0
Consolidating Adjustments
Condensed Financial Statements [Line Items]
Net cash provided by operating activities	[1]			0	0
Cash flows from investing activities:
Business acquisitions, net of cash acquired				0	0
Capital expenditures				0	0
Other, net				0	0
Net cash used by investing activities				0	0
Cash flows from financing activities:
Proceeds from notes				0	0
Proceeds from (repayments of) commercial paper, net				0
Dividends paid				0	0
Purchases of common stock				0	0
Repayment of CSRA accounts receivable purchase agreement				0
Other, net				0	0
Net cash provided (used) by financing activities				0	0
Net cash used by discontinued operations				0	0
Cash sweep/funding by parent				0	0
Net increase in cash and equivalents				0	0
Cash and equivalents at beginning of period				0	0
Cash and equivalents at end of period		0	0	0	0
Consolidating Adjustments | LIBOR
Cash flows from financing activities:
Proceeds from notes				0
Parent Company
Condensed Financial Statements [Line Items]
Net cash provided by operating activities	[1]			(204)	145
Cash flows from investing activities:
Business acquisitions, net of cash acquired				(9,749)	0
Capital expenditures				(36)	(23)
Other, net				93	5
Net cash used by investing activities				(9,692)	(18)
Cash flows from financing activities:
Proceeds from notes				6,461	985
Proceeds from (repayments of) commercial paper, net				1,668
Dividends paid				(801)	(735)
Purchases of common stock				(533)	(1,172)
Repayment of CSRA accounts receivable purchase agreement				0
Other, net				(10)	43
Net cash provided (used) by financing activities				7,785	(879)
Net cash used by discontinued operations				(14)	(28)
Cash sweep/funding by parent				844	1,097
Net increase in cash and equivalents				(1,281)	317
Cash and equivalents at beginning of period				1,930	1,254
Cash and equivalents at end of period		649	1,571	649	1,571
Parent Company | LIBOR
Cash flows from financing activities:
Proceeds from notes				1,000
Guarantor Subsidiaries
Condensed Financial Statements [Line Items]
Net cash provided by operating activities	[1]			1,561	1,503
Cash flows from investing activities:
Business acquisitions, net of cash acquired				(74)	(315)
Capital expenditures				(331)	(205)
Other, net				76	49
Net cash used by investing activities				(329)	(471)
Cash flows from financing activities:
Proceeds from notes				0	0
Proceeds from (repayments of) commercial paper, net				0
Dividends paid				0	0
Purchases of common stock				0	0
Repayment of CSRA accounts receivable purchase agreement				0
Other, net				0	(2)
Net cash provided (used) by financing activities				0	(2)
Net cash used by discontinued operations				0	0
Cash sweep/funding by parent				(1,232)	(1,030)
Net increase in cash and equivalents				0	0
Cash and equivalents at beginning of period				0	0
Cash and equivalents at end of period		0	0	0	0
Guarantor Subsidiaries | LIBOR
Cash flows from financing activities:
Proceeds from notes				0
Non-Guarantor Subsidiaries
Condensed Financial Statements [Line Items]
Net cash provided by operating activities	[1]			(276)	234
Cash flows from investing activities:
Business acquisitions, net of cash acquired				(216)	(49)
Capital expenditures				(80)	(45)
Other, net				0	(2)
Net cash used by investing activities				(296)	(96)
Cash flows from financing activities:
Proceeds from notes				0	0
Proceeds from (repayments of) commercial paper, net				0
Dividends paid				0	0
Purchases of common stock				0	0
Repayment of CSRA accounts receivable purchase agreement				(450)
Other, net				(58)	0
Net cash provided (used) by financing activities				(508)	0
Net cash used by discontinued operations				0	0
Cash sweep/funding by parent				388	(67)
Net increase in cash and equivalents				(692)	71
Cash and equivalents at beginning of period				1,053	1,080
Cash and equivalents at end of period		$ 361	$ 1,151	361	$ 1,151
Non-Guarantor Subsidiaries | LIBOR
Cash flows from financing activities:
Proceeds from notes				$ 0

[1] * Continuing operations only