| Component: (Network and Table) | |
|---|---|
| Network | 00500 - Statement - Consolidated Statements of Cash Flows (http://principal.com/role/StatementConsolidatedStatementsOfCashFlows)  | 
| Table | (Implied) | 
| Reporting Entity [Axis] | 0001126328 (http://www.sec.gov/CIK) | 
| Consolidated Statements of Cash Flows | Period [Axis] | ||
|---|---|---|---|
2016-01-01 - 2016-12-31  | 2015-01-01 - 2015-12-31  | 2014-01-01 - 2014-12-31  | |
Consolidated Statements of Cash Flows  | |||
Operating activities  | |||
Net income (loss)  | 1,361,800,000    | 1,253,200,000    | 1,176,400,000    | 
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:  | |||
Amortization of deferred acquisition costs  | |||
Additions to deferred acquisition costs  | (  | (  | (  | 
Accrued investment income  | (  | (  | |
Net cash flows for trading securities  | (  | (  | |
Premiums due and other receivables  | (  | ||
Contractholder and policyholder liabilities and dividends  | |||
Current and deferred income taxes (benefits)  | (  | ||
Net realized capital (gains) losses  | (171,100,000)   | 51,100,000    | (14,700,000)   | 
Depreciation and amortization expense  | |||
Mortgage loans held for sale, sold or repaid, net of gain  | |||
Real estate acquired through operating activities  | (  | (  | (  | 
Real estate sold through operating activities  | |||
Stock-based compensation  | |||
Other  | (  | (  | |
Net adjustments  | |||
Net cash provided by (used in) operating activities  | |||
Investing activities  | |||
Available-for-sale securities: Purchases  | (  | (  | (  | 
Available-for-sale securities: Sales  | |||
Available-for-sale securities: Maturities  | |||
Mortgage loans acquired or originated  | (  | (  | (  | 
Mortgage loans sold or repaid  | |||
Real estate acquired  | (  | (  | (  | 
Net (purchases) sales of property and equipment  | (  | (  | (  | 
Purchase of interests in subsidiaries, net of cash acquired  | (  | ||
Net change in other investments  | (  | (  | |
Net cash provided by (used in) investing activities  | (  | (  | (  | 
Financing activities  | |||
Issuance of common stock  | |||
Acquisition of treasury stock  | (  | (  | (  | 
Proceeds from financing element derivatives  | |||
Payments for financing element derivatives  | (  | (  | (  | 
Excess tax benefits from share-based payment arrangements  | |||
Purchase of subsidiary shares from noncontrolling interest  | (  | (  | (  | 
Dividends to common stockholders  | (  | (  | (  | 
Dividends to preferred stockholders  | (  | (  | |
Preferred stock redemption  | (  | ||
Issuance of long-term debt  | |||
Principal repayments of long-term debt  | (  | (  | (  | 
Net proceeds from (repayments of) short-term borrowings  | (  | (  | |
Investment contract deposits  | |||
Investment contract withdrawals  | (  | (  | (  | 
Net increase (decrease) in banking operation deposits  | |||
Other  | (  | (  | |
Net cash provided by (used in) financing activities  | (  | (  | |
Net increase (decrease) in cash and cash equivalents  | (  | ||
Cash and cash equivalents at beginning of period  | 2,564,800,000    | ||
Cash and cash equivalents at end of period  | 2,719,600,000    | 2,564,800,000    | 1,863,900,000    | 
Supplemental information:  | |||
Cash paid for interest  | |||
Cash paid for income taxes  | |||
Supplemental disclosure of non-cash activities:  | |||
Assets received in kind for pension risk transfer transactions  | |||